Tool and method for pulling and cutting a Z-axis electrical interconnector

ABSTRACT

A connection portion of a z-axis interconnector is assembled into contact with a plurality of aligned vias in a corresponding plurality of stacked printed circuit boards by gripping and pulling a leader portion of the interconnector connected to the connection portion, to move the interconnector into the final position with the connection portion contacting the aligned vias. The leader portion is severed from the connection portion after the interconnector is moved into the final position. A single pulling and cutting tool which accomplishes these functions preferably does so by a single pinch and cut device having opposing blades which partially penetrate into the leader portion to grip the leader portion, which fully penetrated through the leader portion to sever the leader portion, and which are moved toward and away from the plurality of stacked printed circuit boards to pull the interconnector and to reposition for severing the leader portion.

This invention relates to assembling three-dimensional electronicmodules, and more particularly to a new and improved tool and method forpulling z-axis interconnectors into predetermined positions betweencircuit boards of the module and thereafter cutting off an excessportion of each the z-axis interconnector in a single sequence ofoperations executed rapidly and efficiently to mechanically andelectrically connect the circuit boards and assemble the module. Thez-axis interconnectors are preferably twist pins, which are of the type,and are used in the manner, described in U.S. Pat. Nos. 4,955,523,5,014,419, 5,054,192, 5,045,975, 5,112,232, 5,184,400, 5,189,507,5,195,237, 6,528,759, 6,530,511, 6,584,677, 6,716,038, 6,729,026 and6,971,415, all of which are owned by the assignee of the presentinvention. The subject matter of these prior patents is incorporatedherein by this reference.

BACKGROUND OF THE INVENTION

The evolution of computer and electronic systems has demandedever-increasing levels of performance. In most regards, the increasedperformance has been achieved by electronic components ofever-decreasing physical size. The diminished size itself has beenresponsible for some level of increased performance because of thereduced lengths of the paths through which the signals must travelbetween separate components of the systems. Reduced length signal pathsallow the electronic components to switch at higher frequencies andreduce the latency of the signal conduction through relatively longerpaths.

One technique of reducing the size of the electronic components is tocondense or diminish the space between the electronic components. Adiminished size also allows more components to be included in a system,which is another technique of achieving increased performance because ofthe increased number of components.

A particularly effective approach to condensing the size betweenelectronic components is to attach multiple semiconductor integratedcircuits or “chips” on printed circuit boards, and then stack multipleprinted circuit boards to form a three-dimensional configuration ormodule. Z-axis interconnectors are extended vertically, in the z-axisdimension, between the vertically stacked printed circuit boards, eachof which is oriented in the horizontal x-axis and y-axis dimensions. Theinterconnectors, in conjunction with conductor traces of each printedcircuit board, connect the chips of the module with short signal paths.The relatively high concentration of chips, which are connected by thethree-dimensional, relatively short length signal paths, are capable ofachieving very high levels of functionality.

The z-axis interconnectors contact and extend through plated throughholes or “vias” formed in each of the printed circuit boards. The chipsof each printed circuit board are connected to the vias by conductortraces formed on or within each printed circuit board. The vias areformed in each individual printed circuit board of the three-dimensionalmodules at similar locations, so that when the printed circuit boardsare stacked in the three-dimensional module, the vias of all of theprinted circuit boards are aligned vertically in the z-axis. The z-axisinterconnectors are then inserted vertically through the verticallyaligned vias to establish an electrical contact and mechanicalconnection between the circuit boards, thus assembling the module.

A number of different types of z-axis interconnectors have beenproposed. One particularly advantageous type of z-axis interconnector isknown as a “twist pin.” An example of a prior art twist pin 50 is shownin FIG. 1. The twist pin 50 is formed from a length of wire 52 which hasbeen formed conventionally by helically coiling a number of outerstrands 54 around a center core strand 56 in a planetary manner, asshown in FIG. 2. At selected positions along the length of the wire 52,a bulge 58 is formed by untwisting the outer strands 54 in a reverse oranti-helical direction. As a result of untwisting the strands 54 in theanti-helical direction, the space consumed by the outer strands 54increases, causing the outer strands 54 to bend or expand outward fromthe center strand 56 and create a larger diameter for the bulge 58 thanthe diameter of the regular stranded wire 52. The laterally outwardextent of the bulge 58 is illustrated in FIG. 3, compared to FIG. 2. Thestrands 54 and 56 of the wire 52 have the necessary mechanicalcharacteristics to maintain the shape of the wire in the strandedconfiguration and to allow the outer strands 54 to bend outward at eachbulge 58 when untwisted.

The bulges 58 are formed at selected predetermined distances along thelength of the wire 52 to contact vias 60 in printed circuit boards 62 ofa three-dimensional module 64, as shown in FIG. 4. Contact of the bulge58 with the vias 60 is established by pulling the twist pin 50 throughan aligned vertical column of vias 60. The outer strands 54 of the wire52 have sufficient resiliency characteristics so that the outwardprotruding bulge 58 resiliently presses against an inner surface of asidewall 66 of each via 60, thereby establishing the electrical andmechanical connection between the twist pin 50 and the via 60, as shownin FIG. 5.

To insert the twist pins 50, a leader 68 is extended through thevertically aligned vias 60 of the vertically stacked printed circuitboards 62 (see FIG. 8). The strands 54 and 56 at a terminal end 70 ofthe leader 68 have been welded or fused together to form a rounded endconfiguration 70 to facilitate insertion of the twist pin 50 through thecolumn of vertically aligned vias. The leader 68 is of sufficient lengthto extend through all of the vertically aligned vias 60 of the assembledstacked printed circuit boards 62, before the bulge 58 which adjoins theleader 68 makes contact with the uppermost via 60 of the outermostprinted circuit board 62. The terminal end 70 of the leader 68 extendsbelow the lowermost one of the vertically aligned vias of the lowermostprinted circuit board 62.

The terminal end 70 of the leader 68 is gripped from below and is pulleddownwardly, causing the bulges 58 to move downwardly through thevertically aligned vias 60 until the bulges 58 are all aligned and incontact with the vias 60 of the stacked printed circuit boards. Toposition the bulges in contact with the vertically aligned vias, thelower leading bulges 58 closest to the leader 68 are pulled into and outof the vertically aligned vias until the twist pin 50 arrives at itsfinal desired and assembled position. The resiliency of the bulges 58allows them to move in and out of the vias 60 without losing theirability to make firm contact with the sidewall of the via in the finalassembled position. Once the twist pin is in the final assembledposition, the leader 68 is cut off flush or sub-flush at a predeterminedlength which is slightly beyond the lower surface of the lower printedcircuit board of the module 64, for example no greater than 0.015 inchbeyond the lower surface.

A tail 72 at the other end of the twist pin 50 extends a short distanceabove the upper trailing bulge 58. The strands 54 and 56 at an end 74 ofthe tail 72 are also fused together. The length of the tail 72 positionsthe other end 74 of the twist pin 50 at a similar position above theupper circuit board compared to the position where the leader 68 was cutoff relative to the lower circuit board. Allowing the tail 72 and theremaining portion of the leader 68 to extend slightly beyond the outerprinted circuit boards 62 of the module 64 facilitates gripping thetwist pin 50 when removing it from the module 64 to repair or replaceany defective components.

The twist pins are typically of a very small size. The most common sizesof strands 54 and 56 of the helically-coiled wire 52 used is to formtwist pins 50 are about 0.0016, 0.0033 and 0.0050 in. in diameter. Thediameters of the coiled strands of the wire 52 formed from the thesesizes of strands 54 and 56 are 0.005, 0.0010, and 0.0015 in.,respectively. The typical length of a twist pin having four to sixbulges which extends through four to six printed circuit boards will beabout 1 to 1.5 inches, with the leader constituting about half of thislength. The outer diameter of each bulge 58 will be approximately two tothree times the diameter of the stranded wire 52 in the intervals 76.The tolerance for locating the bulges 58 between intervals 76 is in theneighborhood of 0.002 in. The weight of a typical four-bulge twist pinis about 0.0077 grams, making it so light that handling the twist pin isvery difficult. It is not unusual that a complex module formed by 4 in.by 4 in. printed circuit board 62 may require the use of as many as22,000 twist pins. Thus, the relatively large number of twist pinsnecessary to assemble each three-dimensional module necessitates anability to pull each twist pin into the desired position and to cut theleader off in an efficient and rapid manner.

The common technique for pulling and cutting the twist pins involvesgripping the protruding end 70 of the leader 68 with one machine andpulling the leader downward. Thereafter, a separate machine moves infrom the side and cuts the leader. For a large number of twist pins tobe assembled efficiently in a relatively short amount of time, themovements of the separate pulling machine and cutting machine must becoordinated with one another. Coordinating the functionality of twoindependently operating machines is difficult, and generally requiresvery complex electronic sensors and controllers. Furthermore, becausethe operation of the pulling and cutting machines are independent of oneanother, the functionality of one machine may adversely influence theproper functionality of the other machine. Such prior art pulling andcutting machines are relatively large devices which are intended to beused in a stationary manner. The stacked printed circuit boards must bepositioned and oriented relative to the stationary machines.Consequently, it is impossible, expensive or extremely inconvenient toassemble three-dimensional circuit modules other than by use of thistype of assembly-line equipment. The expense of programming the separatestationary machines is not conducive to the use of the z-axisinterconnectors to assemble relatively smaller numbers of modules.

These and other considerations pertinent to the fabrication of twistpins have given rise to the new and improved aspects of the presentinvention.

SUMMARY OF THE INVENTION

The present invention combines the pulling and cutting functionsnecessary to assemble a z-axis interconnector into vias of a pluralityof stacked printed circuit boards in a series of sequentially-executedoperations. The operations involved in pulling and cutting the z-axisinterconnector are conveniently executed by a single, relatively smalland hand-manipulated mobile machine. The pulling and cutting operationsare interrelated so that each z-axis interconnector is assembled in areliable, consistent and efficient manner. The relatively small size ofthe pulling and cutting tool allows it to be manipulated by hand, sothat an individual can create three-dimensional circuit modules withoutusing large, immobile, expensive and separate assembly-line machineswhich must be coordinated in functionality with a complex controlsystem. Instead, the present invention is capable of implementation as ahand tool, while still obtaining all the precision and functionalitynecessary to assemble z-axis interconnectors into a three-dimensionalelectronic module. The invention can also be implemented as a stationarytool for use in an assembly line if desired, for example.

These and other improvements are accomplished by a pull and cut toolwhich is used for assembling a z-axis interconnector into a plurality ofaligned vias in a corresponding plurality of stacked printed circuitboards. The interconnector has a leader portion which extends throughthe aligned vias when starting to assemble the interconnector, and alsohas a connection portion which contacts the aligned vias upon finishingthe assembly of the interconnector. The tool comprises a pair of bladeswhich move laterally toward and away from one another and longitudinallytoward and away from an outer one of the plurality of stacked printedcircuit boards to execute a sequence in which the leader portion isgripped, the leader portion is pulled a predetermined distance toposition the connection portion in contact with the aligned vias, andthe leader portion is severed from the connection portion at a locationadjacent to the outer one of the plurality of printed circuit boards. Amethod of assembling a z-axis interconnector also accomplishes the abovenoted and other improvements. The assembly method comprises gripping andpulling the leader portion to move the interconnector into the finalposition with the connection portion contacting the aligned vias,severing the leader portion from the connection portion after theinterconnector is moved into the final position, and accomplishing thegripping, pulling and severing with one pinch and cut device.

The tool preferably comprises a gripping and cutting subassembly and alongitudinal movement subassembly. The gripping and cutting subassemblyincludes a pair of blades and a first actuator connected to the bladesto move the blades laterally toward and away from one another. Thelongitudinal movement subassembly is connecting to the gripping andcutting assembly and includes a second actuator connected to move theblades longitudinally toward and away from an outer one of the pluralityof stacked printed circuit boards. A control system is connected to thetool and to the first and second actuators and operative to control thefirst and second actuators to move the blades laterally toward oneanother to penetrate into opposite sides of the leader portion and gripthe leader portion without severing the leader portion, to move theblades longitudinally away from the outer one of the printed circuitboards to pull the interconnector a predetermined distance whichpositions the connection portion in the final position contacting thevias while the leader portion is gripped by the blades, to move theblades laterally away from one another to separate the blades laterallyfrom the leader portion and release the grip on the leader portion afterthe interconnector is pulled into in the final position, to move theblades longitudinally toward the printed circuit boards to return theblades to a predetermined location adjacent to the outer one of theprinted circuit boards while the blades are separated laterally from theleader portion, and to move the blades laterally toward one another topenetrate into the opposite sides of the leader portion sufficiently tosever the leader portion from the connection portion at thepredetermined location.

The method preferably comprises inserting the leader portion of thez-axis interconnector through the aligned vias to establish a startingposition in which a terminal end of the leader portion extends beyond anouter one of the plurality of printed circuit boards, gripping theterminal end of the leader portion with a pinch and cut device when thez-axis interconnector is in the starting position, pulling the leaderportion to move the connection portion of the z-axis interconnectorthrough the plurality of aligned vias to a final position in which theconnection portion contacts the aligned vias by moving the pinch and cutdevice away from the outer one of the printed circuit boards whilegripping the terminal end of the leader portion with the pinch and cutdevice, releasing the grip on the terminal end of the leader portionwith the pinch and cut device after the z-axis interconnector is in thefinal position, positioning the pinch and cut device adjacent to theouter one of the printed circuit boards after the z-axis interconnectorhas been pulled into the final position and after the grip on theterminal end of the leader portion is released, and thereafter severingthe leader portion from the connector portion at a position adjacent tothe outer one of the printed circuit boards by use of the pinch and cutdevice.

Certain other preferable aspects of the tool and the method include thefollowing: using opposing blades to penetrate partially into the leaderportion to grip the leader portion and to penetrate completely throughthe leader portion to sever the leader portion; separating the opposingblades laterally away from the leader portion to release the grip on theleader portion and prior to gripping the leader portion and aftersevering the leader portion; using pressurized fluid to move theopposing blades into the partially penetrated, fully penetrated andlaterally separated positions and to move the pinch and cut device awayfrom the outer one of the printed circuit boards while gripping theleader portion and to position the pinch and cut device adjacent to theouter one of the printed circuit boards after the z-axis interconnectorhas been pulled into the final position and after releasing the grip onthe leader portion; transporting the severed leader portion away fromthe connection portion immediately after severing the leader portion andcollecting a plurality of severed leader portions in a single locationwhich is separated from the pinch and cut device; inserting at least asegment of the leader portion into a conduction tube upon positioningthe pinch and cut device adjacent to the outer one of the printedcircuit boards after the z-axis interconnector has been pulled into thefinal position; and using jaw members with opposing blades of the pinchand cut device to grip the leader portion and contacting the jaw memberswith a deflection mechanism to move the opposing blades laterally towardone another to grip the leader portion.

A more complete appreciation of the present invention and its scope maybe obtained from the accompanying drawings, which are briefly summarizedbelow, from the following detailed descriptions of presently preferredembodiments of the invention, and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a prior art twist pin.

FIG. 2 is an enlarged, cross-sectional view of the twist pin shown inFIG. 1, taken substantially in the plane of line 2-2 in FIG. 1.

FIG. 3 is an enlarged, cross-sectional view of the twist pin shown inFIG. 1, taken substantially in the plane of line 3-3 in FIG. 1.

FIG. 4 is a partial, vertical cross-sectional view of a prior artthree-dimensional module, formed by multiple printed circuit boards andillustrating a fully inserted position of single twist pin of the typeshown in FIG. 1 extending through vertically aligned vias of the printedcircuit boards of the module.

FIG. 5 is an enlarged cross-sectional view of the twist pin within a viashown in FIG. 4, taken substantially in the plane of line 5-5 in FIG. 4.

FIG. 6 is a perspective view of a pulling and cutting tool, and aschematic view of a pneumatic and electrical control system for thetool, in which aspects of the present invention are embodied.

FIG. 7 is an enlarged perspective view of the tool shown in FIG. 6, withcertain portions broken away to reveal a gripping and cuttingsubassembly, a longitudinal movement subassembly, and a pneumaticinterface and leader collection subassembly of the tool.

FIG. 8 is a side elevational view of the twist pin shown in FIG. 1 withits leader inserted through the vertically aligned vias of the printedcircuit boards of the module shown in FIG. 4, prior to positioning thetwist pin in the final assembled position shown in FIG. 4.

FIGS. 9A, 9B, 9C, 9D, 9E and 9F are partial, elevational andcross-sectional views of a portion of a pinch and cut blade of thegripping and cutting subassembly of the tool shown in FIGS. 6 and 7 andof the twist pin and module shown in FIG. 8, illustrating a sequence ofbasic operations performed in moving the twist pin from the initialposition shown in FIG. 8 to the final assembled position within themodule shown in FIG. 4.

FIG. 10 is an exploded perspective view of the gripping and cuffingsubassembly of the tool shown in FIG. 7.

FIG. 11 is an enlarged vertical and longitudinal cross sectional view ofa forward portion of a pinch and cut blade and a blade deflectingmechanism of the gripping and cutting subassembly shown in FIGS. 7 and10, taken substantially in the plane of line 11-11 in FIG. 7, showingthe pinch and cut blade positioned in a forward position relative to theblade deflecting mechanism, resulting in the pinch and cut bladeassuming the position shown in FIGS. 9D and 9F.

FIG. 12 is a cross sectional view similar to the view of FIG. 11, withthe pinch and cut blade positioned in a rearward position relative tothe blade deflecting mechanism, resulting in the pinch and cut bladeassuming the position shown in FIG. 9E.

FIG. 13 is a cross sectional view similar to the views of FIGS. 11 and12, with the pinch and cut blade positioned relative to the bladedeflecting mechanism in an intermediate position compared to thosepositions shown in FIGS. 11 and 12, resulting in the pinch and cut bladeassuming the position shown in FIGS. 9A, 9B, and 9C.

FIG. 14 is an enlarged horizontal and longitudinal cross sectional viewof a forward portion of the gripping and cutting subassembly of the toolshown in FIG. 7, taken substantially in the plane of line 14-14 in FIG.7, illustrating certain aspects of the gripping and cutting subassembly.

FIG. 15 is an enlarged vertical and longitudinal cross sectional view ofa blade activator portion of the gripping and cutting subassembly of thetool shown in FIG. 7, taken substantially in the plane of line 15-15 inFIG. 7.

FIG. 16 is an exploded perspective view of the longitudinal movementsubassembly of the tool shown in FIG. 7.

FIG. 17 is an enlarged vertical and longitudinal cross sectional view ofthe longitudinal movement subassembly taken substantially in the planeof line in 17-17 in FIG. 7, with a longitudinal portion broken away, andwith a piston of the longitudinal movement subassembly in a forwardposition, resulting in movement of the gripping and cutting subassemblyand the pinch and cut blade to the position shown in FIGS. 9A, 9D, 9Eand 9F.

FIG. 18 is a cross sectional view similar to FIG. 17, with a piston ofthe longitudinal movement subassembly in a rearward position, resultingin movement of the gripping and cutting subassembly to the positionshown in FIG. 9C.

FIG. 19 is an enlarged horizontal and longitudinal cross sectional viewof the longitudinal movement subassembly taken perpendicular to the viewof FIG. 17 and substantially in the plane of line 19-19 in FIG. 7.

FIG. 20 is a cross sectional view similar to FIG. 19, with alongitudinal portion broken away, and with the piston positioned asshown in FIG. 18.

FIG. 21 is an exploded perspective view of the pneumatic interface andleader collection subassembly of the tool shown in FIG. 7.

FIG. 22 is an enlarged horizontal and longitudinal cross sectional viewof the pneumatic interface and leader collection subassembly takensubstantially in the plane of line 22-22 in FIG. 7.

FIG. 23 is a transverse cross sectional view of the pneumatic interfaceand leader collection subassembly taken substantially in the plane ofline 23-23 in FIG. 22.

FIG. 24 is a partial perspective view of a rear end of the tool shown inFIGS. 6 and 7, illustrating the passage of pneumatic tubes through arear cap of the pneumatic interface and leader collection subassemblyshown in FIGS. 21-23.

FIG. 25 is a schematic diagram of the pneumatic and electrical controlsystem shown in FIG. 6.

FIG. 26 is a flow chart of the programmed sequence of functions createdby the control system shown in FIG. 25 to cause the tool shown in FIGS.6 and 7 to perform the basic operations illustrated in FIGS. 9A, 9B, 9C,9D, 9E and 9F.

DETAILED DESCRIPTION In General

A twist pin pulling and cutting tool 80 incorporating the presentinvention is shown in FIGS. 6 and 7. The tool includes a housing 82,within which a gripping and cutting subassembly 84, a longitudinalmovement subassembly 86 and a pneumatic interface and leader collectionsubassembly 88 are located. The gripping and cutting subassembly 84includes a pinch and cut blade 90 located at a forward end thereof. Afront shell 92 of the housing 82 generally covers the gripping andcutting subassembly 84, as shown in FIG. 7. A conically shaped front endcap 94 attaches to the front shell 92, and an opening 96 is formed inthe front end cap 94 to permit the pinch and cut blade 90 to extend fromthe housing 82 and interact with the leader 68 of the twist pin 50(FIGS. 1 and 9A-9F) during assembly of the twist pin 50 into its finalposition within the module 64 (FIGS. 4 and 9F).

The longitudinal movement subassembly 86 connects to the gripping andcutting subassembly 84 within the housing 82 and moves the gripping andcutting subassembly 84, and its connected pinch and cut blade 90, in alongitudinal or axial manner within the forward shell 92, during thesequence of operations (FIGS. 9A-9F) involved in assembling the twistpin 50 (FIG. 1) into its final position (FIGS. 4 and 9F). Thelongitudinal movement subassembly 86 is generally located in the middleof the tool 80. An exterior surface of a longitudinal actuator 98 of thelongitudinal movement subassembly 86 forms an intermediate portion ofthe housing 82.

The gripping and cutting subassembly 84 and the longitudinal movementsubassembly 86 execute movements in response to the controlledapplication of pressurized compressed air to those subassemblies to pullthe twist pin 50 (FIG. 1) into a final assembled position within themodule 64 (FIGS. 4 and 9F). After the twist pin 50 has been pulled intoits final assembled position within the module 64, the excess of theleader 68 of the twist pin 50 is severed from the remaining portion ofthe twist pin assembled into the module (FIG. 9E). In addition, thesevered portion of the leader 68 is removed from the gripping andcutting subassembly 84 and the longitudinal movement subassembly 86(FIG. 9F) by the application of vacuum from the interface and collectionsubassembly 88, and the severed leader is collected in a collection cup99 of the interface and collection subassembly 88. By removing andcollecting the severed leaders 68 in this manner, they do not interferewith the rapid, continuous and sequential operation of the tool 80.

The interface and collection subassembly 88 connects the pressurized airto the tool 80 to operate the gripping and cutting subassembly 84 andthe longitudinal movement subassembly 86. The interface and collectionsubassembly 88 also connects the relatively lower pressure air or vacuumto the tool 80 for transporting the severed leader away from thegripping and cutting and longitudinal movement subassemblies 84 and 86.The interface and collection subassembly 88 is located within a rearshell 100 which is attached to the longitudinal actuator 98. A rearshell cap 102 connects to the rear shell 100. Hoses 104, 106, 108, and110 extend through the rear shell cap 102 to supply pressurized air tothe gripping and cutting subassembly 84 and the longitudinal movementsubassembly 86. The hose 112 connects to a fitting on the rear shell cap102 to supply the vacuum to the tool for removing the severed leader andfor purging the vacuum in the collection cup 99 by the application ofpressurized air.

A pneumatic and electrical control system 114 creates the sources ofpressurized air and sub-ambient pressure or vacuum, and connects thosepneumatic sources through the hoses 104-112, as shown in FIG. 6. Thecontrol system 114 responds to control signals 116 and 118 created by anoperator closing foot switches 120 and 122, respectively, to apply thepressurized air and vacuum to the tool 80. The control signals 116 and118 are received by a controller 124 (FIG. 24) of the control system114. The controller 124 executes a program flow (FIG. 26) to deliver thepressurized air and vacuum through the hoses 104-112 to assure theoperation of the tool 80 in response to the operator stepping on oractivating the foot switches 120 and 122 at different points during thesequence of operations involved in assembling the twist pin 50 into themodule 64.

The basic operation of the tool 80 in assembling the twist pin 50 in themodule 64 is illustrated in FIGS. 9A-9F. Use of the tool 80 commencesafter the leader 68 of the twist pin 50 has been inserted through acolumn of aligned vias 60 in the circuit boards 62 of the module 64, asshown in FIG. 8. The leader 68 is of sufficient length to position itsterminal end 70 below and beyond the lowermost circuit board 62. Theextension of the terminal end 70 of the leader 68 beyond the lowermostcircuit board 62 permits it to be gripped by the pinch and cut blade 90,as shown in FIG. 9A.

The pinch and cut blade 90 includes two flexible jaw members 126 and 128which move toward and away from one another as a result of movementimparted to the blade 90 by the gripping and cutting subassembly 84(FIG. 7). The forwardmost terminal ends of the jaw members 126 and 128each include sharp cutting wedges 130 and 132, respectively. The cuttingwedges 130 and 132 face one another across an open space 133 between thejaw members 126 and 128. As shown in FIG. 9A, the jaw members 126 and128 have moved together sufficiently in a partially closed position topinch the cutting wedges 130 and 132 into the sides of the leader 68 atits terminal end 70. The cutting wedges 130 and 132 pinch into the sidesof the leader 68 to a sufficient amount to firmly grip the leader 68without severing it, so that the twist pin 50 can be pulled. The userpositions the tool 80 and the cuffing wedges 130 and 132 adjacent to thelowermost circuit board 62 by the use of a guide member 134, before thejaw members 126 and 128 are moved toward one another to pinch thecutting wedges 130 and 132 into the sides of the leader 68.

Next, as shown in FIG. 9B, the pinch and cut blade 90 is moved downwardrelative to the circuit boards 62 of the module 64, while the jawmembers 126 and 128 maintain the cutting wedges 130 and 132 pinched intothe sides of the leader 68. As the blade 90 moves downward, the housing82 of the tool 80 remains stationary relative to the lowermost circuitboard 62 due to contacting position of the guide member 134 against thelower circuit board. The guide member 134 is connected to the front endcap 94 (also see FIGS. 6 and 7) and serves as a spacer to assure thatthe twist pin 50 is pulled downward the correct amount to position thebulges 58 within each of the vias 60 of the circuit boards 62 in thefinal assembled position (FIG. 4). The guide member 134 includes a notch136 which contacts the side of the leader 68 and aligns the tool 80 withthe leader 68 extending along a center axis 138 of the tool 80. As thedownward movement of the blade 90 pulls the twist pin 50 downwardthrough the circuit boards 62, the leader 68 slides along the notch 136in the guide member 134. The bulges 58 move into and out of the vias 60until the twist pin achieves its final assembled position.

As shown in FIG. 9C, the blade 90 has pulled the twist pin 50 downwardto its predetermined final assembled position where the bulges 58 arelocated within the vias 60 of the circuit board 62 of the module 64. Theextent of downward movement represented in FIG. 9C is established by theamount of longitudinal movement of the longitudinal movement subassembly86 (FIG. 7) in relation to the guide member 134 contacting the lowermostcircuit board 62. With the twist pin 50 pulled into place, the jawmembers 126 and 128 move apart to an open position to release the leader68. The bulges 58 resiliently press against the sidewalls 66 of the vias60 to hold the twist pin 50 in place in the final assembled position.

Next, as shown in FIG. 9D, the pinch and cut blade 90 is moved to anupper cutting position, at which the cutting wedges 130 and 132 areslightly spaced below the lowermost circuit board 62. In order toaccomplish the movement represented by FIG. 9D, the jaw members 126 and128 have been moved to separate transversely from the position shown inFIG. 9C and the cutting wedges 130 and 132 are spaced laterally awayfrom the outside surface of the leader 68. In this open position, thejaw members 126 and 128 and the cutting wedges 130 and 132 do notinterfere with the upward movement of the pinch and cut blade 90 fromthe position shown in FIG. 9C to the position shown in FIG. 9D. The openposition of the jaw members 126 and 128 allows the leader 68 to passbetween the cutting wedges 130 and 132. The guide member 134 keeps thetool 80 positioned with the leader 68 along the center axis 138 whilethe blade 90 is moved upward. This ensures that the leader 68 enters aconduction tube 140 which is positioned concentrically about the centralaxis 138 so that the leader 68 can be cleanly severed and transportedaway from the gripping and pulling subassembly 84 to avoid interferingwith the action of the tool 80 in the next subsequent operation ofpositioning and severing another twist pin 50.

The excess portion of the leader 68 is next severed by lateral inwardmovement of the jaw members 126 and 128 to the fully closed position, asshown in FIG. 9E. The cutting wedges 130 and 132 move together and severthe leader 68 from the portion of the twist pin 50 which remains in thefinal assembled position within the module 64. Movement of the grippingand cutting subassembly 84 causes the jaw members 126 and 128 to movetoward one another and force the cutting wedges 130 and 132 completelythrough the leader 68, thereby severing the external portion of theleader.

Finally, as shown in FIG. 9F, the severed portion of the leader 68 istransported away by the application of vacuum within the conduction tube140. The vacuum transports the severed portion of the leader away fromthe gripping and cuffing subassembly 84 and the longitudinal movementsubassembly 86, where the severed leader 68 is collected within thehollow interior of the collection cup 99 (FIG. 7) of the interface andcollection subassembly 88. Simultaneously with removing the severedportion of the leader 68, the jaw members 126 and 128 are moved awayfrom one another to the open position to ready the jaw members forexecuting the next subsequent operation in which a twist pin is pulledinto the final assembled position and the severed leader is removed.

As can be appreciated from this overview description, the pulling andcuffing tool 80 is conveniently handled and maneuvered by manualmanipulation. The manual manipulation allows each twist pin to beassembled in the final position without the necessity to use relativelycomplex stationary equipment. Moreover, all of the assembly operations,i.e. gripping the twist pin, pulling the twist pin into the finalposition, severing the leader from the remaining assembled portion ofthe twist pin, and removing the severed twist pin, are achieved in arapid continuous sequence. Operating in this manner, the tool 80 iscapable of rapidly and sequentially inserting twist pins to efficientlyassemble the module 64. These same advantageous features are alsoavailable if the tool 80 is incorporated in stationary equipment, suchas that which would be typically used in an assembly line operation.

More details concerning the gripping and cutting subassembly 84, thelongitudinal movement subassembly 86, and the pneumatic interface andsevered leader collection subassembly 88 of the tool 80, and of thepneumatic and electric control system 114, are described below.

Gripping and Cutting Subassembly

The gripping and cutting subassembly 84 is shown in FIGS. 7 and 10-15.The principal function of the gripping and cuffing subassembly 84 is tomove the pinch and cut blade 90 so that it grips the leader 68 bypinching it so that the leader 68 can be pulled (FIGS. 9A, 9B and 9C),and thereafter severing the leader 68 (FIG. 9E). To accomplish theseoperations, the gripping and cutting subassembly 84 includes the pinchand cut blade 90, a blade deflecting mechanism 142 which interacts withthe pinch and cut blade 90 to move the jaw members 126 and 128 andcutting wedges 130 and 132 toward and away from one another, and a bladeactivator 144 which moves the blade deflecting mechanism 142 relative tothe pinch and cut blade 90 to cause the jaw members 126 and 128 to movetoward and away from one another.

The blade activator 144 is preferably of a conventional piston andcylinder construction, in which a piston 146 moves longitudinally withina cylinder 148 (FIGS. 10, 14 and 15) of a cylinder body 150 of the bladeactivator 144. A deflector connection rod 152 is connected at a rear endto the piston 146, and a front end of the connection rod 152 isconnected to the blade deflecting mechanism 142. The connections arepreferably threaded connections. Pressurized air is delivered throughtubes 154 and 156 to the blade activator 144 to move the piston 146longitudinally forward and backward within the cylinder 148. Themovement of the piston 146 is transferred through the deflectorconnection rod 152 to the blade deflecting mechanism 142. The pinch andcut blade 90 is positioned stationarily, and the forward and backwardmovement of the blade deflecting mechanism 142 relative to the blade 90moves the jaw members 126 and 128 into and between the opened, closedand partially closed positions shown in FIGS. 9D, 9E and 9A,respectively.

A blade support bracket 158 connects to and extends longitudinallyforward from the cylinder body 150. A retainer pin 160 extends though ahole 162 in a front end of the support bracket 158. A reduced-diameterportion 164 of the pin 160 extends beyond the support bracket 158 andfits into a hole 166 in a rear end web portion 168 of the blade 90(FIGS. 11-13). In this manner, the blade 90 is connected to a forwardend of the blade support bracket 158, thereby holding the blade 90 in astationary longitudinal position relative to the blade activator 144.However, the pin 160 permits the blade 90 to pivot in a planeperpendicular to an axis through the pin 160.

More details of the pinch and cut blade 90 are shown in FIGS. 11-13. Thepinch and cut blade 90 is formed as an integral single-piece structure,preferably of resilient spring steel. The web portion 168 joins the jawmembers 126 and 128 at a rear end of the blade 90. The hole 166 whichreceives the retainer pin 160 extends through the web portion 168. Whenpositioned within the gripping and cutting subassembly 84, the jawmembers 126 and 128 are generally symmetrically positioned on oppositesides of the center axis 138. The jaw members 126 and 128 extendlongitudinally forwardly and transversely outwardly from the web portion168. The jaw members 126 and 128 are separate from one another exceptwhere they integrally join the blade 90 at the web portion 168. The webportion 168 is transversely offset from the center axis of the tool 80to avoid contacting the conduction tube 140 which extends along thecenter axis 138 (FIG. 14).

Exterior surfaces 170 and 172 of the jaw members 126 and 128,respectively, are smooth and generally symmetrical with respect to acenter line through the blade 90 which is coincident the center axis138. The exterior surfaces 170 and 172 are contacted by the bladedeflecting mechanism 142 to cause the jaw members 126 and 128 to deflecttoward one another. The strength and resiliency of the material fromwhich the blade 90 is made causes the jaw members 126 and 128 to reboundback away one another when the force from the blade deflecting mechanism142 is removed.

Shoulders 174 and 176 extend integrally from the inside surfaces of thejaw members 126 and 128, respectively, along a substantial portion ofthe length of each jaw member 126 and 128. The shoulders 174 and 176extend toward one another across the open space 133 between the jawmembers 126 and 128. The shoulders 174 and 176 reinforce each of the jawmembers 126 and 128 to prevent them from bending substantially when theblade deflecting mechanism 142 contacts and interacts with the exteriorsurfaces 170 and 172. Like the web portion 168, the shoulders 174 and176 are also transversely displaced from the center axis 138 to avoidinterfering with the leader 68 or the conduction tube 140, when the jawmembers 126 and 128 are closed as understood from FIG. 14.

The forward ends of the jaw members 126 and 128 curve longitudinallyforward and transversely inward toward one another and terminate at thecutting wedges 130 and 132. The cutting wedges 130 and 132 are made ofhardened sharpened material. The material of the jaw members 126 and 128also exhibit sufficient strength so that a transverse inward forceapplied by the blade deflecting mechanism 142 to force the jaw members126 and 128 toward one another also brings the cutting wedges 130 and132 toward one another, when severing the leader 68 or when pinching theleader 68 without severing it, as shown in FIGS. 9E and 9A,respectively.

More details of the blade deflecting mechanism 142 are shown in FIGS.10-14. The blade deflecting mechanism 142 includes a clevis 178 which isconnected at a center point to the forward end of the connection rod152. The U-shaped body which defines the clevis 178 projects forwardaway from the connection rod 152, and defines an open space 180 in thecenter of the clevis 178. The pinch and cut blade 90 is positionedwithin the open space 180. A bearing plate 182 is connected to theclevis 178 on one transverse side of the open space 180. An elongatedslot 184 is formed in the bearing plate 182 to receive the retainer pin160. The elongated slot 184 permits the bearing plate 182 and the clevis178 to move forward and backward with respect to the stationary retainerpin 160 as the blade deflecting mechanism 142 moves forward andbackward. A wedge plate 186 is connected to the clevis 178 on theopposite transverse side of the open space 180 from the bearing plate182. The bearing plate 182 and the wedge plate 186 support and retainthe pinch and cut blade 90 between their opposing facing surfaces withinthe open space 180, and provide bearing surfaces along which the blade90 slides when the blade deflecting mechanism 142 moves forward andbackward.

The wedge plate 186 includes a pair of ridges 188 and 190 which projectinto the open space 180 from the wedge plate 184. Cam surfaces 192 and194 are formed on the ridges 188 and 190, respectively, and the camsurfaces 192 and 194 face one another in that portion of the space 180between the ridges 188 and 190. The jaw members 126 and 128 of the blade90 fit in the space between the ridges 188 and 190. The cam surfaces 192and 194 contact the exterior surfaces 170 and 172 of the jaw members 126and 128, respectively. The cam surfaces 192 and 194 extend forwardly andtransversely outward in a similar manner to the forward and transverselyoutward extension of the exterior surfaces 170 and 172. The cam surfaces192 and 194 are also symmetrical about the center line 138.

Forward longitudinal movement of the clevis 178 and the attached wedgeplate 186 forces the ridges 188 and 190 with their cam surfaces 192 and194 to slide forward along the exterior surfaces 170 and 172 of the jawmembers 126 and 128, respectively. The fixed distance between the camsurfaces 192 and 194 forces the jaw members 126 and 128 to deflect moreclosely together, as the cam surfaces 190 and 192 move forward along theexterior surfaces 170 and 172. In a similar manner, rearwardlongitudinal movement of the clevis 178 slides the cam surfaces 192 and194 rearwardly with respect to the exterior surfaces 170 and 172,allowing the resiliency of the material from which the blade 90 isformed to move the jaw members 126 and 128 outwardly away from oneanother. With the blade deflecting mechanism 142 moved to its mostrearward position, a slight clearance exists between the cam surfaces192 and 194 and the exterior surfaces 170 and 172, allowing the jawmembers 126 and 128 to separate fully in the open position.

More details concerning the blade activator 144 are shown in FIGS.10-15. The cylinder body 150 defines the cylinder 148 along which thepiston 146 moves. The cylinder 148 extends from a front end of thecylinder body 150 to a rear end of the body 150. The piston 146 has anexterior diameter that allows it to fit within the cylinder 148.Longitudinally spaced annular grooves 196 and 198 circumscribe thepiston 146. The grooves 196 and 198 receive sealing rings 200 and 202which hermetically seal the piston 146 within the cylinder 148. A frontcylinder cap 204 is attached to the front end of the cylinder body 150,and a rear cylinder cap 206 is attached to the rear end of the cylinderbody 150. The piston 146 moves within the cylinder 148 between the frontand rear cylinder caps 204 and 206.

The front cylinder cap 204 has a generally square connection flange 208with a rearward extending cylindrical projection 210. The connectionflange 208 is attached to front end of the cylinder body 150 with screws211. The cylindrical projection 210 has an exterior diameter that isslightly smaller than the interior diameter of the cylinder 148. Withthe flange 208 attached to the cylinder body 150, the cylindricalprojection 210 extends rearwardly into the cylinder 148 from the frontend of the cylinder body 150. A sealing ring 212 fits within an annularrecess 214 formed in the exterior of the cylindrical projection 210, andthe sealing ring 212 establishes a hermetic seal between the front cap204 and the cylinder body 150 within the cylinder 148.

The front cylinder cap 204 has a front bore 216 through which theconnecting rod 152 extends. A front rod seal 218 is positioned within anannular groove 220 in the front bore 216 and contacts the exteriorsurface of the connecting rod 152. The front rod seal 218 establishes ahermetic seal around the connecting rod 152 where it exits from thefront cylinder cap 204. A rear end of the connecting rod 152 connects tothe piston 146 within the cylinder 148. In this manner, longitudinalforward and backward movement of the piston 146 within the cylinder 148is transferred through the connecting rod 152 to the blade deflectingmechanism 142.

The rear cylinder cap 206 is a somewhat similar construction to thefront cylinder cap 204. The rear cylinder cap 206 has a generally squareconnection flange 222 with a forward extending cylindrical projection224. The connection flange 222 is attached to rear end of the cylinderbody 150 with screws 225. The cylindrical projection 224 has an exteriordiameter that is slightly smaller than the interior diameter of thecylinder 148. With the flange 222 attached to the cylinder body 150, thecylindrical projection 224 extends forwardly into the cylinder 148 fromthe rear end of the cylinder body 150. A sealing ring 226 fits within anannular recess 228 formed in the exterior of the cylindrical projection224, and a sealing ring 226 establishes a hermetic seal between the rearcap 206 and the cylinder body 150 within the cylinder 148.

The rear cylinder cap 206 has a rear bore 230 through which a rodextension 232 extends. A rear rod seal 234 is positioned within anannular groove 236 in the rear bore 230 and contacts the exteriorsurface of the rod extension 232. The rear rod seal 230 establishes ahermetic seal around the rod extension 232, where the rod extension 232exits from the rear cylinder cap 206. A front end of the rod extension232 connects by threads to the rear side of the piston 146 within thecylinder 148. In this manner, the rod extension 232 moves longitudinallyforward and backward with the corresponding movement of the piston 146within the cylinder 148. The rear end of the rod extension 232 extendsrearwardly from the rear cap 206, is centered generally about the centeraxis 138 and extends to the longitudinal movement subassembly 86 (FIGS.7 and 16).

As shown in FIGS. 14 and 15, the connecting rod 152 and the rodextension 232 are hollow, and thereby define interior passageways 238and 240 through the rod 152 and the rod extension 232, respectively. Acentral hole 242 is formed through the piston 146 in alignment with theinterior passageways 238 and 240 of the connecting rod 152 and the rodextension 232. As shown in FIGS. 11-13, the clevis 178 has a hole 244formed through it in alignment with the interior passageway 238 of theconnecting rod 152. In this manner, an unobstructed internal passageway246 extends through the hole 244 in the clevis, the interior passageway238 of the connecting rod 152, the central hole 242 of the piston 146,and the interior passageway 240 of the rod extension 232. Thepassageways 238 and 240 and the holes 242 and 244 are generally coaxialabout the central axis 138.

The conduction tube 140 is located within the interior passageway 246defined by the passageways 238 and 240 and the holes 242 and 244. Theconduction tube 140 conducts the severed leaders 68 away from thecutting blade 90 of the gripping and cutting subassembly 84, asdiscussed in conjunction with FIG. 9F. A forward end of the conductiontube 140 is positioned longitudinally along the center axis 138 in thespace 133 and between the jaw members 126 and 128. The forward end ofthe conduction tube 140 is also slightly flared to help direct theterminal end 70 of the leader 68 into the conduction tube 140, to ensurethat the severed leader 68 enters and is transported through theconduction tube 140, as shown in FIG. 9F.

Fluid passageways 248 and 250 are formed forwardly from the rear end ofthe cylinder body 150, and the passageways 248 and 250 open into thecylinder 148 at positions which are at the front and rear sides of thepiston 146, respectively, as shown in FIG. 15. The passageways 248 and250 provide a hermetically sealed path through the cylinder body 150 andinto the cylinder 148. Conventional hose fittings 252 are attached tothe rear end of the cylinder body 150 at positions which surround thefluid passageways 248 and 250. The hose fittings 252 are positioned onthe top and bottom of the flange 222 of the rear cylinder cap 206. Aflexible connection sleeve 254 is attached to each forward end of thetubes 154 and 156. Each connection sleeve 254 is slipped over a hosefitting 252 in a conventional friction-fit connection. A retainingtubing clamp 256 slides over that portion of the connection sleeve 254which surrounds the hose fitting 252, to firmly maintain the connectionof each connection sleeve 254 to one hose fitting 252.

Compressed air is supplied through the tubes 154 and 156 and into thefluid passageways 248 and 250, respectively, to move the piston 146longitudinally within the cylinder 148. Compressed air in the fluidpassageway 250 enters the portion of the cylinder 148 between the piston146 and the rear cylinder cap 206. The pressurized air admitted throughthe passageway 250 forces the piston 146 to move longitudinallyforwardly within the cylinder 148. The longitudinal forward movement ofthe piston causes the blade deflecting mechanism 142 to move forwardrelative to the stationary pinch and cut blade 90, thereby pinching thejaw members 126 and 128 toward one another, to establish the closed orpartially closed position of the jaw members (FIGS. 9E and 9A). Applyingcompressed air at a relatively higher pressure through the fluidpassageway 250 creates a relatively greater forward longitudinalmovement of the piston 146, resulting in greater deflecting force on thejaw members, which results in severing the leader 68 from the remainingportion of the twist pin 50 (FIG. 9E) as a result of moving the cuttingwedges 130 and 132 into contact with one another, as the jaw members 126and 128 move to the fully closed position. Applying compressed air at arelatively lower pressure through the fluid passageway 250 createsrelatively lesser longitudinal movement of the piston 146, resulting inlesser deflecting force on the jaw members, which results in grippingthe leader 68 (FIG. 9A) as a result of moving the cutting wedges 130 and132 toward but not contacting one another, as the jaw members move intothe partially closed position.

Compressed air supplied through the fluid passageway 248 enters theportion of the cylinder 148 between the piston 146 and the frontcylinder cap 204. The pressurized air admitted through the passageway248 forces the piston 146 to move longitudinally rearwardly within thecylinder 148. The longitudinal rearward movement of the piston 146causes the blade deflecting mechanism 142 to move rearward relative tothe stationary pinch and cut blade 90, thereby allowing the jaw members126 and 128 to move away from one another and establish the openposition of the jaw members (FIGS. 9D and 9F).

As has been discussed previously, the entire gripping and cuttingsubassembly 84 moves longitudinally within the interior of the frontshell 92 and front end cap 94, as a result of longitudinal forward andbackward movement applied by the longitudinal movement subassembly 86.The entire gripping and cutting subassembly 84 is restrained againstrotation while it is moved longitudinally forward and backward withinthe front shell 92 by a non-rotating plate 258, shown in FIGS. 7, 10 and14. The non-rotating plate 258 attaches to the interior sidewall of thefront shell 92. An exterior cylindrically curved surface portion 260 ofthe non-rotational plate 258 conforms to the inside surface of the frontshell 92. A generally planar and flat bearing plate 262 attaches to thenon-rotational plate 258 and faces outward toward the center axis of thetool 80. The bearing plate 262 is preferably formed of afriction-reducing material such as plastic or Teflon. The cylinder body150 includes a flat surface 264 which faces and contacts an adjoiningflat surface of the bearing plate 262. The flat surface 264 of thecylinder body 150 slides along the flat bearing plate 262 when thegripping and cutting subassembly 84 is moved longitudinally.

Upper and lower surfaces 266 and 268 (FIG. 10) of the cylinder body 150generally have the same cylindrical curvature as the inside surface ofthe front shell 92. The curved surfaces 266 and 268 are closely adjacentto the inside surface of the front shell 92. The close adjacency of thecurved surfaces 266 and 268 with the inside surface of the front shell92 maintains the flat surface 264 of the cylinder body 150 in contactthe flat bearing plate 262, thereby preventing rotational movement ofthe cylinder body 150 and the attached blade deflecting mechanism 142and pinch and cut blade 90 as the gripping and cutting assembly 84 moveslongitudinally forward and backward.

Longitudinal Movement Subassembly

The longitudinal movement subassembly 86 shown in detail in FIGS. 7 and16-20. The principal function of the longitudinal movement subassembly86 is to move the gripping and cutting subassembly 84 longitudinallywithin the tool 80, thereby pulling the gripped twist pin 50 into thefinal desired position (FIGS. 9B and 9C) and returning the gripping andcutting subassembly 84 to a position where the pinch and cut blade 90can sever the leader 68 at the desired location (FIG. 9D). To accomplishthese operations, the longitudinal movement subassembly 86 includes alongitudinal activator 270. The longitudinal activator 270 is preferablyof a conventional piston and cylinder construction, in which a piston272 is moveably positioned within a cylinder 274 of a cylinder body 276.A longitudinal movement connection rod 278 is connected at its rear endto the piston 272, and a front end of the longitudinal movement rod 278is connected to the blade activator 144. Longitudinal movement of thepiston 272 within the cylinder 274 is transferred by the connection rod278 to the blade activator 144, thereby longitudinally moving of thegripping and cutting subassembly 84. Compressed air for moving thepiston 272 in the cylinder 274 is supplied to the longitudinal activator270 through the pneumatic interface and leader collection subassembly88.

More details concerning the longitudinal activator 270 are shown inFIGS. 16-20. The cylinder body 276 defines the cylinder 274 along whichthe piston 272 moves. The cylinder 274 extends from a front end of thecylinder body 276, which faces toward the gripping and cuttingsubassembly 84 (FIG. 7), to a rear end of the cylinder body 276, whichfaces toward the pneumatic interface and leader collection subassembly88 (FIG. 7). The piston 272 has an exterior diameter that is slightlysmaller than the interior diameter of cylinder 274, allowing the piston272 to be positioned within the cylinder 274 and to slide longitudinallywithin the cylinder 274. Longitudinally spaced annular recesses 280 and282 circumscribe the piston 272. The recesses 280 and 282 receivesealing rings 284 and 286 which hermetically seal the piston 272 withinthe cylinder 274.

A front cylinder cap 288 is attached to the front end of the cylinderbody 276. A bore 290 extends through the front cylinder cap 288, and abushing 292 is positioned within the bore 290. The bushing 292 fitsaround the longitudinal connection rod 278 to guide the connection rod278 as it moves longitudinally forward and backward relative to thefront cylinder cap 288. The bore 290 also includes an annular recess 294within which an O-ring seal 296 is positioned. The O-ring seal 296creates a hermetic seal at the bore 290 between the front cylinder cap288 and the connection rod 278.

The front cylinder cap 288 also includes a rearward extendingcylindrical projection 298. The cylindrical projection 298 has aslightly smaller outside diameter than the diameter of the cylinder 274,thereby allowing the cylindrical projection 298 to extend rearwardlyinto the forward end of the cylinder body 276. An annular shaped recess300 extends circumferentially around the cylindrical projection 298, andholds a sealing ring 302. The sealing ring 302 creates a hermetic sealbetween the front cylinder cap 288 and the cylinder body 276.

A stop plate 304 is attached to the forward facing surface of the frontcylinder cap 288. A cylindrical-shaped protrusion 306 extends forwardlyfrom the forward surface of the front cylinder cap 288 and fits within asimilarly-shaped, rearwardly-facing cylindrical recess 308 formed in arearward facing surface of the stop plate 304, thereby aligning the stopplate 304 with the front cylinder cap 288. The stop plate 304 preventsthe bushing 292 from moving longitudinally forward and out of the bore290 of the front cylinder cap 288. A center hole 310 extends through thestop plate 304. The longitudinal connection rod 278 extends through thehole 310.

A hard stop collar 312 fits around the longitudinal connection rod 278.The stop collar 312 is used to control the amount of longitudinalrearward movement of the longitudinal connection rod 278 and the piston272 within the cylinder 274. Rearward movement of the connection rod 278brings the stop collar 312 into contact with the forward facing side ofthe stop plate 304, thereby limiting further longitudinal rearwardmovement of the connection rod 278 and the piston 272 within thecylinder 274. Adjusting the position of the stop collar 312 on theconnection rod 278 adjusts the extent that the gripping and cuttingsubassembly 84 can be moved longitudinally rearward. The maximum amountof longitudinal rearward movement defines the distance that the leader68 is pulled (FIG. 9C) to position the bulges 58 of the twist pin 50 inthe vias 60 of the circuit bore 62 of the module 64 (FIGS. 4 and 9C-9F).

The hard stop collar 312 is generally of an annular configuration with aslot 314 formed radially through a wall of the collar 312. A center hole316 is formed through the stop collar 312, and the longitudinalconnection rod 278 extends through the center hole 316. An adjustmentbolt 318 extends across the slot 314 between the portions of the stopcollar 312 that are separated by the slot 314. Tightening the adjustmentbolt 318 diminishes the distance across the slot 314 and slightlydecreases the internal diameter of the center hole 316. Decreasing theinternal diameter of the center hole 316 compresses the hard stop collar312 at the center hole 316 around the connection rod 278 and therebyfrictionally retains the stop collar 312 to the connection rod 278.Loosening the adjustment bolt 318 increases the diameter of the centerhole 316 and allows the position of the stop collar 312 to be adjustedand moved longitudinally along the connection rod 278.

The position of the stop collar 312 along the longitudinal connectionrod 278 is adjustable within the tool 80. As shown in FIG. 6, anadjustment opening 320 is formed in the front shell 92 by which toaccess the adjustment bolt 318. A tool which interacts with theadjustment bolt 318, such as a socket or an Allen wrench, is insertedthrough the opening 320, to loosen the adjustment bolt 318. Thereafter,the position of the stop collar 312 on the connection rod 278 ismanually adjusted by moving the gripping and cutting subassembly 84until the measured distance of the cutting wedges 130 and 132 from theguide member 134 is equal to the distance that the twist pin is to bepulled. The stop collar 312 is tightened to the connection rod 278 atthis position with the stop collar 312 abutting the stop plate 304. Inthis manner, the rearward extent of pulling movement available from thelongitudinal activator 270 is established.

The rear end of the longitudinal connection rod 278 is attached rigidlyto the piston 272. The rear end of the connection rod 278 is threaded,and is connected to corresponding threads formed in axial bore 322 inthe piston 272. The front end of the connection rod 278 is alsothreaded, and the front end threads connect with internal threads formedin a rearward-facing protrusion 323 of the rear cylinder cap 206 of theblade activator 144 (FIGS. 7, 10, 15, 17 and 19). In this manner, alongitudinally rigid connection extends between the piston 272 in thelongitudinal activator 270 and the blade activator 144 of the grippingand cutting subassembly 84. Because of this rigid mechanical connection,the movement of the piston 272 within the cylinder 274 controls thelongitudinal movement of the connection rod 278, as limited by theposition of the stop collar 312 on the connection rod 278.

A rear cylinder cap 324 is attached to the rear end of the cylinder body276. The rear cylinder cap 324 has a construction somewhat related tothe construction of the front cylinder cap 288. The rear cylinder cap324 includes a forward extending cylindrical projection 326. Thecylindrical projection 326 has a slightly smaller outside diameter thanthe diameter of the cylinder 274, thereby allowing the forward extendingcylindrical projection 326 to extend into the rear end of the cylinder274. An annular shaped recess 328 extends circumferentially around thecylindrical projection 326 and holds a sealing ring 330. The sealingring 330 creates a hermetic seal between the rear cylinder cap 324 andthe cylinder body 276.

The rear cylinder cap 324 defines a bore 332 through which an extensiontube 334 extends. A forward end of the extension tube 334 is attached tothe piston 272 by a threaded connection. The extension tube 334therefore moves longitudinally forward and backward with correspondingmovement of the piston 272. The length of the extension tube 334 issufficient to maintain a rear end of the extension tube 334 rearwardlyoutside of the rear cylinder cap 324, even when the piston 272 moveslongitudinally forward to the maximum extent permitted by the frontcylinder cap 288. The bore 332 in the rear cylinder cap 324 includes abushing 336 which extends around and provides a guide for the extensiontube 334. An internal annular shaped recess 338 is also formed withinthe bore 332, and an O-ring 340 is positioned in the recess 338. TheO-ring 340 establishes a hermetic seal between the bore 332 and theextension tube 334 as the extension tube 334 slides longitudinallywithin the bore 332.

The longitudinal connection rod 278 is hollow and the extension tube 334is hollow, as shown in FIG. 17-20. The axial bore 322 in the piston 278aligns with the hollow interiors through the connection rod 278 and theextension tube 334. In this manner, an unobstructed internal passageway341 extends along the center axis 138 through the longitudinal activator270. The internal passageway 341 aligns with the internal passageway 246through the blade activator 144 to conduct the severed leaders 68 fromthe conduction tube 140 through the longitudinal activator 270 and intothe collection cup 99 of the interface and collection subassembly 88(FIG. 7).

Compressed air for moving the piston 272 in the cylinder 274 is suppliedthrough fluid passageways 342 and 344, shown in FIGS. 16, 19 and 20. Thefluid passageways 342 and 344 extend longitudinally forward through therear cylinder cap 324 and the cylinder body 276, and open into thecylinder 274 at positions which are located between the piston 272 andthe cylindrical projection 298 of the front cylinder cap 288 and betweenthe piston 272 and the cylindrical projection 326 of the rear cylindercap 324, respectively. The passageways 342 and 344 are formed in thecylinder body 276 but are sealed where they enter the cylinder 274.Consequently, the passageways 342 and 344 define hermetically sealedpaths for conducting the pressurized air into the cylinder 274.Pressurized air in the fluid passageway 342 enters the cylinder 274between the front cap 288 and the piston 272 and forces the piston 272rearwardly within the cylinder 274. The rearward movement of the pistonmoves the blade activator 144 and the other attached components of thegripping and cutting subassembly 84 rearwardly. This rearward movementoccurs in conjunction with pulling the twist pin 50 (FIGS. 9A-9C) intothe final assembled position. Pressurized air in the passageway 344enters the cylinder 274 between the rear cap 324 and the piston andforces the piston 272 forwardly within the cylinder 274. The forwardmovement of the piston moves the blade activator 144 and the otherattached components of the gripping and cutting assembly 84 forwardly.This forward movement occurs after the twist pin has been pulled intothe final assembled position after which the pinch and cut blade 90 ismoved forwardly to the location to sever the leader 68 from theremaining portion of the twist pin 50 (FIG. 9D).

Conventional hose fittings 346 and 348 are attached to the rear cylindercap 324 to communicate with the fluid passageways 342 and 344,respectively. The hose fittings 346 and 348 connect to the pressurehoses 108 and 110 (FIG. 6) to conduct the pressurized air from thosehoses into the fluid passageways 342 and 344, respectively. With thecylinder body 276 assembled into the tool 80, as shown in FIG. 6, thefluid passageways 342 and 344 are horizontally positioned on oppositetransverse sides of the center axis 138 (FIGS. 19 and 20). Accordingly,the fluid passageways 342 and 344 occupy three o'clock and nine o'clockpositions when the cylindrically-shaped cylinder body 276 is viewed fromthe rear end.

Two additional fluid passageways 350 and 352 are formed longitudinallythrough the rear cylinder cap 324, the cylinder body 276 and the frontcylinder cap 288 as shown in FIGS. 16, 17 and 18. The fluid passageways350 and 352 are vertically positioned on opposite transverse sides ofthe center axis 138. The fluid passageways 350 and 352 therefore occupythe 12 o'clock and six o'clock positions when viewing the cylinder body276 from the rear end. Holes 354 and 356 are formed through the stopplate 304 in alignment with the fluid passageways 350 and 352,respectively.

The rear ends of the tubes 154 and 156, which extend rearwardly from theblade activator 144, project through the holes 354 and 356 in the stopplate 304 and into the fluid passageways 350 and 352, respectively.O-rings 358 and 360 are positioned in annular grooves 362 and 364,respectively, formed in the front cylinder cap 288 surrounding theportion of the fluid passageways 350 and 352 which extend through thefront cylinder cap 288. The O-rings 358 and 360 allow the upper andlower tubes 154 and 156 to slide longitudinally forward and rearwardthrough the O-rings 358 and 360 while keeping the rearward ends of thetubes 154 and 156 in the passageways 350 and 352 and while maintaining ahermetic seal around the tubes 154 and 156. The passageways to 350 and352 are formed in the cylinder body 276 but are sealed by the O-rings358 and 360 to maintain a hermetic seal between the passageways 350 and352 and the tubes 154 and 156.

Conventional hose fittings 366 and 368 are attached to the rear cylindercap 324 to communicate with the fluid passageways 350 and 352,respectively. The hose fittings 366 and 368 connect to the pressurehoses 104 and 106 (FIG. 6) to conduct the pressurized air from thosepressure hoses into the fluid passageways 350 and 352. The pressurizedair in the passageways 350 and 352 is communicated through the tubes 154and 156 to the blade actuator 144. Although not shown, O-rings may bepositioned in circumferential grooves which surround the passageways342, 344, 350 and 352 at the interfaces between the rear cylinder cap324, the cylinder body 276 and the front cylinder cap 288, therebymaintaining hermetic seals between the components 324, 276 and 288 andthe passageways 324, 344, 350 and 352 through those components.

Pneumatic Interface and Leader Collection Subassembly

The pneumatic interface and leader collection subassembly 88 is shown inFIGS. 7 and 21-24. The principal function of the subassembly 88 is toconnect the pressurized air and vacuum supplied through the hoses104-112 to the tool 80 and to collect the severed leaders 68 in a mannerwhich does not interfere with the operation of the gripping and cuttingsubassembly 84 and the longitudinal movement subassembly 86. Theoperations of the interface and collection subassembly 88 are achievedprimarily within the rear shell 100 to which the rear cap 102 isattached.

A partial circumferential slot 370 is formed in the rear cap 102 at alocation which is radially spaced from the center axis 138, as shown inFIGS. 21-23. The hoses 104-110 extend through the slot 370 into aninterior space defined within the rear shell 100. Once within theinterior of the rear shell 100, the forward ends of the hoses 104-110connect to the hose fittings 346, 348, 366 and 368. In this manner,pressure hoses 104-110 pneumatically interface with the tool 80.

A center bore 372 is formed through the rear cap 102 coaxially with thecenter axis 138. An elongated cylindrically-shaped vacuum chamber 374 isinserted through the center bore 372. A forward end 376 of the chamber374 has a hole 378 formed therein coaxially with the center axis 138.The hole 378 is slightly larger in diameter than the outside diameter ofthe extension tube 334. The rear end of the extension tube 334 extendsthrough the hole 378 into the interior of the vacuum chamber 374. Aflexible elastomeric seal 380 is positioned in the forward end 376 ofthe vacuum chamber 374. The seal 380 contacts and circumscribes theextension tube 334 to establish a hermetic seal between the extensiontube 334 and the interior of the vacuum chamber 374, as the extensiontube 334 moves forward and backward within the center bore 372. The seal380 also functions as a wiper to scrape or dislodge severed leaders 68collected in the collection cup 99 from contact with the extension tube334. The forward end 376 of the vacuum chamber 374 contacts the rearcylinder cap 324 and prevents the bushing 336 from moving longitudinallyrearward out of the bore 332 in the rear cylinder cap 324.

The vacuum chamber 374 is open at its rear end and throughout itsinterior from the open rear end to the closed forward end 376. Aconnection flange 382 (FIGS. 21 and 24) extends transversely outwardfrom the vacuum chamber 374 at the open rear end. Mounting holes 384 areformed through the flange 382. Thumb screws 386 pass through themounting holes 384 and screw into the rear cap 102.

The collection cup 99 is formed in the shape of an elongated cup with acylindrically shaped sidewall 388 and a rear end plate 390 which closesthe cylindrically shaped sidewall 388 at a rear end of the collectioncup 99. The rear end plate 390 extends transversely outward beyond thesidewall 388 at the rear end of the collection cup 99 to create a flange392. The flange 392 is captured under the tightened thumb screws 386 tohold the collection cup 99 in the vacuum chamber 374 and in the tool 80.The forward end of the cylindrical sidewall 388 is open. The sidewall388 has an outside diameter that is slightly smaller than the insidediameter of the vacuum chamber 374, permitting the collection cup 99 tobe inserted within the hollow interior of the vacuum chamber 374.

The collection cup 99 extends into the vacuum chamber 374 until its openfront end is closely adjacent to the forward end 376 of the vacuumchamber 374. In the fully inserted position, the flange 392 of thecollection cup 99 rests against the flange 382 of the vacuum chamber 374at the rear surface of the rear cap 102. The thumb screws 386 includecontact shoulders 394 (FIG. 21) which contact the collection cup flange392 and apply axial force to the flange 392 to force it against theflange 382 of the vacuum chamber 374 and thereby retain the collectioncup 99 within the vacuum chamber 374 and retain both the collection cup99 in the vacuum chamber 374 within the interior of the rear shell 102of the tool 80.

A filter 396 is connected through an opening formed in the end plate390. A hose connection 398 is connected to the filter 396. The vacuumhose 112 is connected to the hose connection 398, at the exterior rearend of the tool 80. Vacuum pressure conducted through the hose 112 isthereby applied through the hose connection 398 and the filter 396 andinto the interior of the collection cup 99. In this manner the vacuumhose 112 is interfaced with the tool 80.

An annular shaped recess 400 is formed in the sidewall 388 of thecollection cup 99, and an O-ring 402 is retained by the recess 400. TheO-ring 402 is radially compressed against the inner surface of thevacuum chamber 374 to create a hermetic seal between the collection cup99 and the vacuum chamber 374. Consequently, the vacuum conductedthrough the hose 112 and into the interior of the collection cup 99 isalso applied into the interior of the vacuum chamber 374, through theinternal passageway 341 of the longitudinal activator 270, through theinternal passageway 246 of the blade activator 144 (FIG. 15), and intothe collection tube 140 (FIG. 14). The vacuum applied in this mannerpropels the severed leaders 68 from the pinch and cut blade 90 into thehollow interior of the collection cup 99. The filter 346 prevents thecollected leaders 68 from entering into the vacuum hose 112 through thehose connection 396.

The severed leaders 68 accumulate in the collection cup 99 during thecontinued use of the tool 80 to assemble the twist pins 50 into themodules 64. When it is necessary to remove the severed leaders 68 fromthe collection cup 99, the thumb screws 386 are removed from the rearcap 102, and the collection cup 99 is removed from within the interiorof the vacuum chamber 374. The severed leaders are then removed from thecollection cup 99. Thereafter, the collection cup 99 is reassembled intothe tool by inserting it into the vacuum chamber 374 and reattaching thethumb screws 386. The vacuum hose 112 connected to the hose connection398 exhibits sufficient flexibility to permit the collection cup 99 tobe removed from the tool 80 and maneuvered to remove the collectedsevered leaders, without disconnecting the hose 112 from the hoseconnection 398.

Control System

The control system 114 for the tool 80 is shown in FIG. 25. The primaryfunctions of the control system 114 are to create sources of pressurizedair and sub-ambient pressure or vacuum which are used to operate thetool 80, and to control the application of the pressurized air and thevacuum to the tool 80 in response to activation of the foot switches 120and 122 by the operator of the tool 80. The pressurized air is createdby a conventional compressor 404. The pressurized air is supplied fromthe compressor 404 to a distribution manifold 406. The source of vacuumis created by flowing pressurized air from the distribution manifold 406through a conventional venturi 408. Electrically controlled pneumaticsolenoid valves 410, 412, 414, 416, 418, 420 and 422 assume and changeflow states in response to solenoid control signals 424, 426, 428, 430,432, 434 and 436 applied to the solenoids 410, 412, 414, 416, 418, 420and 422, respectively, to conduct the pressurized air and the vacuumthrough the hoses 104, 106, 108, 110 and 112 to the tool 80. The controlsignals 424-436 are supplied by the controller 124 in response to theinput control signals 116 and 118 from the foot switches 120 and 122,respectively.

The compressor 404 compresses ambient air and provides the compressedair at a relatively high output pressure level to a filter 438. Thefilter 438 removes particles that may be present in the compressed airsupplied by the compressor 404. A pressure switch 440 is connected tosense the pressure of the relatively high pressure output air conductedthrough the filter 438. If the pressure drops below a predeterminedminimum threshold, the pressure switch 440 sends a control signal 442 tothe controller 124 and the controller ceases all operation of the tool80. The controller 124 resets itself when adequate pressure isre-established, as determined by the signal 442. Upon resetting, thecontroller 124 sends solenoid control signals 424-436 to the solenoidvalves 410-422 to establish an initial state of readiness of the tool 80for assembling twist pins 50 into circuit modules 64.

The compressed air from the compressor 404 is supplied to a regulator444 which reduces the high output pressure from the compressor 404 to asomewhat lower level within the distribution manifold 406. A secondpressure regulator 446 is connected to the distribution manifold 406 andreduces the pressure of the air from the distribution manifold 406 evenlower. The air pressure in the manifold 406 established by the regulator444 is relatively higher than the relatively lower pressure establishedby the second pressure regulator 446. The relatively lower pressure airfrom the pressure regulator 446 is used to grip the leader 68 (FIGS.9A-9C).

The solenoid valves 410-422 each have two pneumatic input ports and asingle pneumatic output port. The two input ports are shown in FIG. 25on the left-hand side of the solenoid valves 410-422, and the singleoutput port is shown in FIG. 25 on the right-hand side of the solenoidvalves 410-422. The upper one of the two input ports of the solenoidvalves 412, 414, 416, 418, 420 and 422, as shown in FIG. 25, is directlyconnected to the manifold 406 to receive the relatively higher pressurefrom the manifold 406. The lower one of the two input ports of thesolenoid valves 412, 414, 416 and 418, as shown in FIG. 25, is directlyconnected to ambient air pressure. The lower one of the two input portsof the solenoid valves 420 and 422, as shown in FIG. 25, is hermeticallysealed so that no flow path and no pressure application may becommunicated to or through the solenoid valves 420 and 422 from thoseinput ports. The upper one of the two input ports of the solenoid valve410, as shown in FIG. 25, is directly connected to the second pressureregulator 446, to receive the relatively lower pressure supplied by thepressure regulator 446. The lower one of the two input ports of thesolenoid valve 410, as shown in FIG. 25, is directly connected toambient air pressure.

Connected in the manner described in the preceding paragraph, turning onthe solenoid valve 410 results in the solenoid valve 410 fluidlyconducting the relatively lower pressure from the regulator 446 to acheck valve 448. Turning off the solenoid valve 410 results in thesolenoid valve 410 fluidly conducting atmospheric pressure to the checkvalve 448. Turning on the solenoid valve 412 results in the solenoidvalve 412 fluidly conducting the relatively higher pressure from themanifold 406 to the check valve 448. Turning off the solenoid valve 412results in the solenoid valve 412 fluidly conducting atmosphericpressure to the check valve 448. Turning on the solenoid valve 414results in it fluidly conducting the relatively higher pressure from themanifold 406 to the hose 104. Turning off the solenoid valve 414 resultsin it fluidly conducting atmospheric pressure to the hose 104. Turningon the solenoid valve 416 results in it fluidly conducting therelatively higher pressure from the manifold 406 to the hose 108.Turning off the solenoid valve 416 results in it fluidly conductingatmospheric pressure to the hose 108. Turning on the solenoid valve 418results in it fluidly conducting the relatively higher pressure from themanifold 406 to the hose 110. Turning off the solenoid valve 418 resultsin it fluidly conducting atmospheric pressure to the hose 110. Turningon the solenoid valve 420 results in it fluidly conducting of therelatively higher pressure from the manifold 406 to the hose 112.Turning off the solenoid valve 420 results in it not conducting anyfluid or communicating any fluid pressure to the hose 112, because itslower input port (as shown in FIG. 25) is hermetically sealed. Turningon the solenoid valve 422 results in it fluidly conducting therelatively higher pressure from the manifold 406 to the venturi 408. Therelatively higher pressure flowing through the venturi 408 creates avacuum or subatmospheric pressure which is supplied to the hose 112.Finally, turning off the solenoid valve 420 results in it not conductingany fluid or communicating any fluid pressure to the venturi 408,because its lower input port (as shown in FIG. 25) is hermeticallysealed.

The check valve 448 directs the higher of two different pressuresapplied to its two input ports to its output port. The lower of the twodifferent pressures applied to one input port has no influence on thehigher pressure applied to the other input port. The check valve 448conducts the higher pressure and the accompanying fluid flow to theoutput port of the check valve 448. Thus, in the circumstance where theturned on solenoid valve 410 applies the relatively lower pressure fromthe regulator 446 to one input port of the check valve 448 and theturned off solenoid valve 412 applies ambient pressure to the otherinput port of the check valve 448, the check valve 448 conducts therelatively lower pressure from the regulator 446 to the hose 106. In thecircumstance where the turned on solenoid valve 412 applies therelatively higher pressure from the distribution manifold 406 to oneinput port of the check valve 448 and the turned off the solenoid valve410 applies ambient pressure to the other input port of the check valve448, the check valve 448 conducts the relatively higher pressure fromthe distribution manifold 406 to the hose 106, and the relatively lowerpressure from the regulator 446 has no influence on the relativelyhigher pressure conducted to the hose 106.

The solenoid valves 410, 412 and 414 are designated as a grip solenoidvalve, a cut solenoid valve, and an open solenoid valve, respectively.Turning on and turning off the grip, cut and open solenoid valves 410,412 and 414 control the movement of the piston 146 within the cylinder148 of the blade activator 144 (FIGS. 10-15) to create the partiallyclosed, closed and open positions of the pinch and cut blade 90,respectively.

When the operator steps on or activates the grip pull/abort foot switch120, the control signal 116 is supplied to the controller 124, and thecontroller 124 delivers the solenoid control signals 424, 426 and 428 tothe grip, cut and open solenoid valves 410, 412 and 414 to control theblade activator 144 and cause the pinch and cut blade 90 to grip theleader 68. The control signal 424 turns on the grip solenoid valve 410to connect the relatively lower pressure compressed air from theregulator 446 to one input port of the check valve 448. The controlsignal 426 turns off the cut solenoid valve 426 and causes it to supplyambient pressure to the other input port of the check valve 448. Underthese conditions, the relatively lower pressure from the regulator 446is supplied through the hose 106 into the cylinder 148. The controlsignal 428 turns off the open solenoid valve 414 and causes it to supplyambient pressure through the hose 106 to the cylinder 148. Therelatively higher pressure from the hose 106 and the ambient pressurefrom the hose 104 establish a pressure differential across the piston146 which moves the piston 146 partially forward in the cylinder 148.The connection rod 152, which is connected to the piston 146, moves theblade deflecting mechanism 142 forward with only enough force to deflectthe jaw members 126 and 128 so that the cutting wedges 130 and 132 (FIG.13) pinch and grip the leader 68 of the twist pin 50 without severing it(FIGS. 9A-9C). The relatively lower output pressure from the regulator446 is adjustable to control the extent to which the cutting wedges 130and 132 pinch into of the leader 68 without severing it. Adjusting theamount of the relatively lower pressure air in this manner is useful toaccommodate twist pins having different thicknesses.

When the operator steps on or activates the cut/purge foot switch 122,the control signal 118 is supplied to the controller 124, and thecontroller 124 delivers the solenoid control signals 424, 426 and 428 tothe grip, cut and open solenoid valves 410, 412 and 414 to control theblade activator 144 to sever the leader 68. The control signal 426 turnson the cut solenoid valve 412 to connect the relatively higher pressurecompressed air from distribution manifold 406 to one input port of thecheck valve 448. The control signal 424 turns off the grip solenoidvalve 410 and causes it to apply ambient pressure to the other inputport of the check valve 448. The relatively higher pressure conductedthrough the cut solenoid valve 412 is conducted by the check valve 448through the hose 106 and into the cylinder 148. The control signal 428turns off the open solenoid valve 414 and causes it to conduct ambientpressure air through the hose 106 and into the cylinder 148. Therelatively higher pressure compressed air from the hose 104 and theambient pressure from the hose 106 create a relatively greater pressuredifferential across the piston 146, compared to the pressuredifferential across the piston 146 when gripping the leader 68. Therelatively greater pressure differential moves the piston 146 forward inthe cylinder 148 to a greater extent. The connection rod 152 moves theblade deflecting mechanism 142 forward with enough force to deflect thejaw members 126 and 128 so that the cutting wedges 130 and 132 (FIG. 12)sever the leader 68 from the remaining portion of the twist pin 50 (FIG.9E). The relatively higher output pressure from the regulator 444 isadjustable to obtain sufficient force on the cutting wedges 130 and 132to sever the leader 68. Adjusting the amount of the relatively higherpressure air in this manner is useful to accommodate twist pins havingdifferent thicknesses.

The solenoid valves 416 and 418 are designated as a pull solenoid valveand a return solenoid valve, respectively. The pull and return solenoidvalves 416 and 418 control the movement of the piston 272 within thecylinder 274 of the longitudinal activator 270 to move the gripping andcutting subassembly 84.

When the operator steps on or activates the grip pull/abort foot switch120, the control signal 116 is supplied to the controller 124, and thecontroller 124 delivers the solenoid control signals 430 and 432 to thepull and return solenoid valves 416 and 418 to control the longitudinalactivator 270 to move the gripping and cutting subassembly 84longitudinally to pull the twist pin into the final assembled positionand to return the subassembly 84 to the position for severing the leader68. The control signal 430 turns on the pull solenoid valve 416 toconnect the relatively higher pressure compressed air from thedistribution manifold 406 through the hose 108 and into the cylinder274. The control signal 430 turns off the return solenoid valve 418 tocause it to conduct ambient pressure through the hose 110 and into thecylinder 274. The resulting pressure differential moves the piston 272rearward in the cylinder 274. The movement of the piston 272 within thecylinder 274 is transferred by the connection rod 278 to the grippingand cutting subassembly 84, and moves that subassembly 84 rearwardlyaway from the lower circuit board 62 of the module 64 (FIGS. 9B and 9C).During this rearward movement of the gripping and cutting subassembly84, the leader 68 is gripped by the pinch and cut blade 90.Consequently, the leader 68 is pulled into position.

Shortly after the leader 68 is pulled into the assembled position (FIG.9C), the controller 124 delivers the solenoid control signals 430 and432 to the pull and return solenoid valves 416 and 418 to control thelongitudinal activator 270 to return the gripping and cuttingsubassembly 84 to a position where the leader 68 can be severed. Thecontrol signal 432 turns on the return solenoid valve 418 and itconducts the relatively higher pressure compressed air from thedistribution manifold 406, through the hose 110 and into the cylinder274. The control signal 430 turns off the pull solenoid valve 416 andcauses it to communicate ambient pressure through the hose 108 into thecylinder 274. The pressure differential on the piston 272 moves thepiston forward within the cylinder 274, and the connection rod 278transfers that motion to the gripping and cutting subassembly 84,thereby moving the subassembly 84 forward and toward the lower circuitboard 62 of the module 64 (FIG. 9D).

The solenoid valves 420 and 422 are designated as a purge solenoid valveand a vacuum solenoid valve, respectively. The purge and vacuum solenoidvalves 420 and 422 control the application of relatively high pressureand vacuum into the collection cup 99, respectively. The relatively highpressure and vacuum are communicated to the tool 80 through the hose112. The vacuum communicated through the hose 112 transports the severedleader 68 away from the pinch and cut blade 90 of the gripping andcutting subassembly 84 (FIGS. 9E and 9F) and into the collection cup 99in the manner previously described. The application of relatively highpressure to the collection cup 99 has the effect of clearing or purgingany severed leaders or any other obstructions which might inadvertentlyremain within the conduction tube 140, the internal passageway 246 inthe blade activator 144 (FIG. 14), and/or the internal passageway 341 inthe longitudinal activator 270 (FIG. 17). Such obstructions wouldprevent transporting the next severed leader 68 into the collection cup99, if those obstructions were not removed. The application of therelatively high pressure to the collection cup 99 clears anyobstructions by transporting them in the reverse direction through thepassageways 341 and 246 and out of the forward end of conduction tube140 (FIGS. 14 and 17).

When the operator steps on or activates the cut/purge foot switch 122,the control signal 118 is supplied to the controller 124, and thecontroller 124 delivers the solenoid control signals 434 and 436 to thepurge and vacuum solenoid valves 420 and 422 to apply vacuum to thecollection cup 99. The control signal 436 turns on the vacuum solenoidvalve 422 to conduct pressurized air through it to the venturi 408. Thepressurized air flows through the venturi 408 and creates vacuum whichis supplied through the hose 112 and into the collection cup 99. Thevacuum is communicated from the collection cup 99 through the internalpassageways 341 and 246 (FIGS. 14 and 17) and into the conduction tube140, thereby removing the severed leader 68 (FIG. 9F). The controlsignal 434 turns off the purge solenoid valve 420. The turned off purgesolenoid valve 420 does not adversely influence the vacuum appliedthrough the hose 112 because of its communication to its hermeticallysealed input port when turned off.

After completing the grip, pull, return and sever or cut operationsinvolved in assembling a twist pin 50 into the module 64 (FIG. 4), orwithout completing a sever or cut operation, the controller 124 deliversthe solenoid control signals 434 and 436 to the purge and vacuumsolenoid valves 420 and 422 to apply relatively higher pressure air intothe collection cup 99. The control signal 434 turns on the purgesolenoid valve 420 to conduct the higher pressure air from the manifold406 through the hose 112 and into the collection cup 99. The higherpressure air in the collection cup 99 is communicated through theinternal passageways 246 and 341 and into the conduction tube 140 (FIGS.14 and 17), thereby blowing out or purging any severed leader or otherobstructions from within those passageways 246 and 341 and theconduction tube 140. The control signal 436 turns off the vacuumsolenoid valve 422. The turned off vacuum solenoid valve 422 does notadversely influence the relatively high pressure applied through thehose 112 because of its communication to its hermetically sealed inputport when turned off.

The controller 124 preferably includes or is constituted by amicroprocessor or microcontroller which has been programmed to respondto the control signals 116, 118 and 442 in the manner described. Inresponse, the controller 124 supplies the solenoid control signals424-436 which have the described effect of controlling the applicationof the relatively high and relatively low pressure air and vacuum to thetool 80 to cause it to operate in the manner described. Thefunctionality of the controller 124 in causing the tool 80 to executethe gripping, pulling, cutting and purging operations during theassembly of the twist pin 50 (FIGS. 9A-9F) are illustrated by a flowchart of the program sequence 450 shown in FIG. 26.

Program Flow Sequence

The preferred sequence 450 of functions involved in operating andcontrolling the tool 80 is shown in FIG. 26. The sequence 450 isdescribed in conjunction with the control system 114 shown in FIG. 25.Each of the steps or functions of the sequence 450 is identified by areference number in FIG. 26.

The sequence 450 begins or starts at 452, after which the controller 124operates all of the solenoid valves 410-422 of the control system 114(FIG. 25) to the off position, thereby creating an initialized state454. The initialized state at 454 places the tool 80 in a state ofreadiness for assembling a twist pin 50 into a circuit board module 64by commencing a grip and pull operation 464, an abort operation 466, acut operation 470 and a purge operation 472 involved in and availablefor use in assembling a twist pin 50 into a circuit board module 64.

From the initialized state 454, the sequence 450 progresses to adetermination at 456 of whether one of the grip pull/abort or cut/purgefoot switches 120 or 122 (FIGS. 6 and 25) has been pressed or activatedby the operator. The controller 124 determines whether either footswitch 120 or 122 was activated at 456 by sensing the presence of eitherfoot switch control signal 116 or 118 (FIG. 25). Until activation ofeither of the foot switch occurs, the sequence 450 is in a wait loopcreated by the negative determination at 456 leading to reconsiderationof the foot switch activation condition determined at 456.

Pressing or activating the grip pull/abort foot switch 120 initiates agripping and pulling operation 464 of the tool 80 in which the leader ofthe twist pin is gripped and the twist pin is thereafter pulled untilthe twist pin is in the desired inserted position within the circuitboard module (FIGS. 9A-9C). Pressing or activating the grip pull/abortfoot switch 120 also initiates an abort operation 466 of the tool 80 inwhich a previously inserted but not cut twist pin is gripped and pulledfrom its inserted position within the circuit board module withoutcompleting its assembly into the circuit board module. In essence, anabort operation 466 removes a previously inserted twist pin before theleader of that twist pin is cut to complete the assembly of the twistpin in the circuit board module.

Pressing or activating the cut/purge foot switch 122 initiates thecutting operation 470 in which the leader of the twist pin is cut offadjacent to the lowermost circuit board of the circuit board module andthe severed leader is removed (FIGS. 9D-9F) from the conduction tube 140and the internal passageways 246 and 341 and transferred into thecollection cup 99 (FIGS. 14, 15, 17-21). Pressing or activating thecut/purge foot switch 122 also initiates a purge operation 472 in whichthe application of relatively high pressure has the effect of clearingor purging any severed leaders or any other obstructions which mightinadvertently remain within the conduction tube 140, the internalpassageway 246 in the blade activator 144 (FIG. 14), and/or the internalpassageway 341 in the longitudinal activator 270 (FIG. 17). Suchobstructions would prevent transporting the next severed leader 68 intothe collection cup 99, if those obstructions were not removed. The purgeoperation 472 clears any obstructions by transporting them in thereverse direction through the passageways 341 and 246 and out of theforward end of conduction tube 140 (FIGS. 14 and 17).

Whenever one of the foot switches 120 or 122 is pressed or activated, anaffirmative determination at 456 moves the sequence 450 out of the waitloop at 456 to a determination at 458. The determination at 458identifies which of the foot switches 120 or 122 (FIG. 25) has beenactivated. The determination at 458 is made by the controller 124 inresponse to the asserted foot switch control signal 116 or 118 (FIG. 25)created by activation of the foot switch 120 or 122.

Activation of the grip pull/abort foot switch 120 moves the sequence 450to 460 where another determination is made as to whether the last orpreceding foot switch activation was an activation of the cut/purge footswitch 122 (FIG. 25). After the tool 80 has been placed in aninitialized state at 454, the first determination at 460 is negative,since there is no previous activation of the foot switch from theinitialized state. The program flow moves to 462 where anotherdetermination is made as to whether the last operation performed by thetool 80 was a grip pull operation. Again, since the tool is in theinitialized state and there has been no previous operation of any type,the determination at 462 is negative. Under these circumstances, a grippull operation is executed at 464. After completion of the grip pulloperation 464, the sequence 450 reverts back to the determination at456, awaiting another activation of a foot switch.

When previous operations have been performed by the tool 80, thesequence 450 reaches the determination 460 under circumstances whereactivation of one of the foot switches 120 or 122 has caused one of theoperations 464, 466, 470 or 472 to have occurred previously. Thedetermination at 460 allows the sequence 450 to progress to a grip andpull operation 464 only after a cut operation 470 or a purge operation472, as recognized by an affirmative determination at 460. Anaffirmative determination at 460 establishes that the leader of thepreviously installed twist pin has been cut, and under suchcircumstances, another twist pin can be installed by the gripping andpulling operation 464.

Under circumstances where the previous operation was not a cut or purgeoperation resulting from activation of the cut/purge foot switch 122,the sequence 450 progresses from 460 to the grip and pull operation 464only under the circumstances where the previous operation performed wasnot a grip and pull operation, as established by a negativedetermination at 462. In this case, the prior operation was an abortoperation 466, or the first operation after initialization, and thenegative determination at 462 allows the grip and pull operation 464 tobe accomplished.

If the last operation executed was a grip pull operation, as establishedby an affirmative determination at 462, the sequence 450 executes anabort operation 466. The abort operation 466 provides the tool 80 withthe capability to remove a twist pin from the circuit board modulebefore it is completely installed and assembled into the circuit boardmodule. For example, the wrong twist pin may have been inadvertentlyinserted into the circuit board module, or the inserted twist pin may bedefective, or the inserted twist pin may be positioned improperly. Underthese and other similar situations, the capability to remove apreviously installed twist pin is desirable. The abort operation 466 isbasically a grip pull operation which has the effect of pulling thetwist pin from the circuit board module. Once pulled from the circuitboard module, the twist pin must be removed from the tool 80, typicallyby executing a purge operation 472. After execution of the abortoperation 466, the sequence 450 reverts back to 456.

Aborting the previous installation of a twist pin is accomplished bysequentially activating the grip pull/abort foot switch 120 a secondtime in sequence after first activating the grip pull/abort foot switchto accomplish a gripping and pulling operation 462 which installed thetwist pin in the first instance and without activating the cut/purgefoot switch. Under such circumstances, the second sequential activationof the grip pull/abort foot switch is detected at 456, and the sequence450 is directed from the determination at 458 to the determination at460. The determination at 460 is negative because no cut or purgeoperations have been performed. The next determination at 462 isaffirmative, because the previous operation performed was the grip pulloperation that resulted in the assembly of the twist pin in the circuitboard module which is now desired to be removed. The affirmativedetermination at 462 results in the performance of an abort operation at466.

The determination at 462 has the effect of toggling the operationsperformed by sequential activations of the grip pull/abort foot switch120 between the grip and pull operation 464 and the abort operation 466.So long as the cut/purge foot switch 122 is not activated, thedetermination at 462 alternately causes a twist pin to be inserted bythe gripping and pulling operation 464 or an inserted twist pin to beremoved by an abort operation 466. Once the twist pin has been properlyinserted, a cut and purge operation will be accomplished by activatingthe cut/purge foot switch 122.

When the operator of the tool 80 is satisfied that a twist pin has beenproperly inserted as a result of a grip and pull operation 464, theoperator activates or presses the cut/purge foot switch 122. Theactivation of the foot switch 122 is sensed at 456, and activation ofthe cut/purge foot switch is detected at 458. At 468, it is determinedwhether the last activation of a foot switch was for a grip pulloperation. Under circumstances of an affirmative determination at 468, acut operation 470 is performed. The affirmative determination at 468arises only under circumstances where the twist pin has been properlyinserted in the circuit board module and thereafter it is desired to cutthe leader of the twist pin. Under such circumstances, the cut operationis executed at 470 and the sequence 450 reverts back to 456.

In order to purge the severed leader from within the tool 80, or anyother obstruction such as the twist pin removed during an abortoperation 466, the cut/purge foot switch 122 is activated or pressed asecond time in sequence after the first press has resulted in executionof the cut operation 470. The second sequential activation of thecut/purge foot switch 122 is recognized at 456 and is determined at 458and leads to the determination at 468. In this case, a negativedetermination occurs at 468 because the previous activation of thecut/purge foot switch was to execute a cut operation 470. The negativedetermination at 468 results in execution of the purge operation 472.

After the first activation of the cut/purge foot switch 122 which leadsto the cut operation 470, all subsequent sequential activations of thatcut/purge foot switch will result in the accomplishment of purgeoperations at 472, due to the negative determination at 468. In otherwords, after the cut operation 470 has been performed and the grippull/abort foot switch 120 has not been activated thereafter, allsubsequent activations of the cut/purge foot switch 122 after a grippull operation has been performed will result in performance of purgeoperations 472, until the grip pull/abort foot switch 120 has beenactivated and a grip pull operation 464 has been accomplished. In thismanner, there is an assurance that a cut operation 470 will be performedonly when a twist pin has been inserted into the circuit board module.All other activations of the cut/purge foot switch 122 result in purgeoperations 472, and this operation is beneficial in clearingobstructions even if multiple purge operations are required to do so, oris harmless if there is no obstruction to purge.

The grip pull, abort, cut and purge operations 464, 466, 470 and 472,respectively, and the initialization state 454, are accomplished by thecontroller 124 delivering the solenoid control signals 424-436 to thegrip solenoid valve 410, the cut solenoid valve 412, the open solenoidvalve 414, the pull solenoid valve 416, the return solenoid valve 418,the purge solenoid valve 420 and the vacuum solenoid valve 422,respectively, as shown in FIG. 25.

To perform the grip pull operation 464 (FIG. 26), the controller 124sends the solenoid control signals to turn off the pull solenoid valve416, to turn off the cut solenoid valve 412, to turn off the gripsolenoid valve 410 and turn on the open solenoid valve 414. Thecontroller 124 then executes a slight time delay and then sends thesolenoid control signal to turn on the return solenoid valve 418,resulting in moving the open pinch and cut blade 90 into position forthe gripping the leader 68 of the twist pin 50. Another time delay isexecuted, followed by the controller 124 sending solenoid controlsignals to turn off the open solenoid valve 414, to turn on the gripsolenoid valve 410 and to turn off the return solenoid valve 418. Underthese circumstances, the relatively lower pressure air passes throughthe turned-on grip solenoid valve 410 and the two-way check valve 448 tomove the blade deflecting mechanism 142 (FIG. 13) and cause the cuttingwedges 130 and 132 of the pull and cut blade 90 to pinch into and gripthe leader 68 of the twist pin (FIG. 9A). After another slight timedelay, the controller 124 sends a solenoid control signal to turn on thepull solenoid valve 416. The gripped leader 68 is pulled (FIG. 9B) as aresult of the turned-on pull solenoid valve 416 moving the gripping andcutting subassembly 84 and the gripping cutting wedges 130 and 132 ofthe pinch and cut blade 90 to pull the twist pin 50 into place in themodule 64 (FIG. 9C). Thereafter, the controller 124 executes anotherslight time delay, followed by sending control signals to turn off thegrip solenoid valve 410 and to turn on the open solenoid valve 414. Atthis point, the functions of the grip and pull operation 464 arecomplete.

To perform the abort operation 466 (FIG. 26), the controller 124 sendssolenoid control signals to turn off the grip solenoid valve 410, toturn off the cut solenoid valve 412, to turn on the open solenoid valve414, to turn off the pull solenoid valve 416, and to turn on the returnsolenoid valve 418. Under these circumstances the pinch and cut blade 90is returned to the position for gripping the leader which extends fromthe circuit board module. The controller 124 thereafter executes aslight time delay, followed by sending solenoid control signals to turnoff the return solenoid valve 418 to turn off the open solenoid valve414 and to turn on the grip solenoid valve 410. Under thesecircumstances the cutting wedges 130 and 132 of the pull and cut blade90 pinch into and grip the leader of the twist pin. Another slight timedelay is executed by the controller 124, followed by sending a solenoidcontrol signal to turn on the pull solenoid valve 416. The turned-onpull solenoid valve 416 moves the gripping and cuffing subassembly 84and the gripping and cutting wedges 130 and 132 of the pinch and cutblade 90 to pull the twist pin completely out of the circuit boardmodule. Another delay is executed, followed by sending solenoid controlsignals to turn off the pull solenoid valve 416 and to turn on the opensolenoid valve 414. At this point, the functions occurring in the abortoperation 464 are complete.

To perform the cut operation 470 (FIG. 26), the controller 124 sendssolenoid control signals to turn off the grip solenoid valve 410, toturn off the cut solenoid valve 412, to turn off the pull solenoid valve416 and to turn on the open solenoid valve 414. After executing a slighttime delay, the controller 124 then sends a solenoid control signal toturn on the return solenoid valve 418. Under these circumstances, thepinch and cut blade 90 is moved to the position for cutting the leaderwhich extends from the circuit board module (FIG. 9D). Another delay isexecuted, and the controller 124 thereafter sends solenoid controlsignals to turn off the open solenoid valve 414, to turn on the vacuumsolenoid valve 422 and to turn on the cut solenoid valve 412. Underthese conditions, the cutting wedges 130 and 132 of the pinch and cutblade 90 thereafter sever the leader (FIG. 9E) as a result of theturned-on cut solenoid valve 412. At this point, since the severedleader 68 is in the conduction tube 140, and the vacuum applied from thevacuum solenoid valve 422 starts transporting the leader 68 into thecollection cup 99 (FIG. 21). The controller 124 executes another delay,followed by sending solenoid control signals to turn off the cutsolenoid valve 412 and to turn on the open solenoid valve 414. Underthese circumstances the cutting wedges 130 and 132 move away from oneanother (FIG. 9F). The vacuum remains on to continue transporting thesevered leader to the collection cup, and that vacuum remains on duringanother time delay executed by the controller 124, thereby assuring thatenough vacuum is produced to fully transport the severed leader into thecollection cup. Finally, the controller 124 sends a solenoid controlsignal to turn off the vacuum solenoid valve 422. At this point, thefunctions occurring in the cut operation 470 are complete.

To perform the purge operation 472 (FIG. 26), the controller 124 sendssolenoid control signals to turn off the cut solenoid valve 412, to turnoff the grip solenoid valve 410, to turn on the open solenoid valve 414,to turn off the pull solenoid valve 416 and to turn on the returnsolenoid valve 418. Turning on the open solenoid valve 414 opens thepinch and cut blade 90 and turning on the return solenoid valve 418moves the gripping and cutting subassembly 84 forward. The controller124 thereafter executes a delay, followed by turning on the purgesolenoid valve 420. The turned-on purge solenoid valve 420 blowscompressed air through the collection tube 99 and the internalpassageways 246 and 341 and the collection tube 140 (FIGS. 14, 17 and22) to clear any severed leader, obstruction or aborted twist pin whichmight be present in those passageways. The controller 124 thereafterexecutes another time delay followed by sending a solenoid controlsignal to turn off the purge solenoid control valve 420. At this point,the functions occurring in the purge operation 472 are complete.

If at any time during the execution of the sequence 450, the controller124 receives a low-pressure control signal 442 from the pressure switch440, the controller 124 ceases functioning. Thereafter, controller 124resets itself when adequate pressure is re-established. When thecontroller 124 resets, the initialization state 454 (FIG. 26) isachieved, and the sequence 450 then transitions from the initializationstate 454 to the determination at 456 waiting for the activation of afoot switch 120 or 122 for continued functionality in the mannerdescribed above.

As has been described above, the pulling and cutting tool 80 combinesthe gripping, pulling and cutting operations necessary to positionz-axis interconnectors in a three-dimensional module, into a single,relatively small, conveniently manipulated and mobile machine. Thesingle tool 80 accomplishes all operations necessary to assemble az-axis interconnect in a circuit module, thereby avoiding the use ofseparate machines for pulling the twist pins and for cutting the twistpins. The relatively compact size of the pulling and cutting tool allowsit to be manipulated by hand, for convenient and quick assembly of thez-axis interconnectors. The use of large, immobile and expensiveseparate machines, which must be coordinated operationally with acomplex control system, and which consume considerable space in anassembly line, is avoided. Despite its small size and manualpositioning, the tool 80 achieves significant precision in pulling thetwist pins to the desired position within the circuit module, by theprecise movement available from the longitudinal activator 270 of thelongitudinal movement subassembly 86. The precision available from thegripping and cutting subassembly 84 allows the leader 68 to be pinchedso that it can be pulled but without severing the leader, but stillsevers the leader at the appropriate point in the sequence of assemblyoperations. The convenient operability of the tool 80 allows the user toassemble a relatively large number of the z-axis interconnectors intothe circuit module relatively quickly, thereby saving manufacturingexpenses. Many other advantages and improvements will become apparentupon fully appreciating the many benefits of the present invention.

A presently preferred embodiment of the present invention and many ofits improvements have been described with a degree of particularity.This description is a preferred example of implementing the invention,and is not necessarily intended to limit the scope of the invention. Thescope of the invention is defined by the scope of the following claims.

1. Apparatus for assembling a z-axis interconnector into a plurality ofaligned vias in a corresponding plurality of stacked printed circuitboards, the interconnector having a leader portion which extends throughthe aligned vias in a start position upon beginning to assemble theinterconnector and also having a connection portion which contacts thealigned vias in a final position upon completing assembly of theinterconnector, the apparatus comprising: a pull and cut tool comprisinga gripping and cutting subassembly and a longitudinal movementsubassembly; the gripping and cutting subassembly including a pair ofblades and a first actuator connected to the blades to move the bladeslaterally toward and away from one another; the longitudinal movementsubassembly connecting to the gripping and cutting assembly andincluding a second actuator connected to move the blades longitudinallytoward and away from an outer one of the plurality of stacked printedcircuit boards; and a control system connected to the tool and to thefirst and second actuators and operative to control the first and secondactuators to: move the blades laterally toward one another to penetrateinto opposite sides of the leader portion and grip the leader portionwithout severing the leader portion, move the blades longitudinally awayfrom the outer one of the printed circuit boards to pull theinterconnector a predetermined distance which positions the connectionportion in the final position contacting the vias while the leaderportion is gripped by the blades, move the blades laterally away fromone another to separate the blades laterally from the leader portion andrelease the grip on the leader portion after the interconnector ispulled into in the final position, move the blades longitudinally towardthe printed circuit boards to return the blades to a predeterminedlocation adjacent to the outer one of the printed circuit boards whilethe blades are separated laterally from the leader portion, and move theblades laterally toward one another to penetrate into the opposite sidesof the leader portion sufficiently to sever the leader portion from theconnection portion at the predetermined location.
 2. Apparatus asdefined in claim 1, wherein: the control system comprises a source ofgrip fluid pressure at a first predetermined pressure level and a sourceof cut fluid pressure at a second predetermined pressure level which isdifferent from the first predetermined pressure level; the firstactuator imparts movement in response to an application of fluidpressure to the first actuator; the control system selectively conductsthe grip fluid pressure to the first actuator to move the bladeslaterally to grip the leader portion; and the control system selectivelyconducts the cut fluid pressure to move the blades laterally to severthe leader portion from the connection portion.
 3. Apparatus as definedin claim 2, wherein: the first actuator comprises a cylinder, a pistonmovable within the cylinder, and a rod connected to the piston andextending from the cylinder to impart the movement from the firstactuator; the application of the grip and cut fluid pressures cause thepiston to move within the cylinder and the rod to move with respect tothe cylinder; and the movement of the rod relative to the cylinder inresponse to the grip and cut fluid pressures moves the blades to gripand sever the leader portion, respectively.
 4. Apparatus as defined inclaim 3, wherein: the gripping and cutting subassembly further comprisesa blade mechanism and a deflecting mechanism which are operativelyconnected to the cylinder and the rod to move relative to one another;the blade mechanism comprises a pair of laterally opposed andlongitudinally outwardly projecting jaw members, the jaw members havingfront ends to which the blades are connected; the deflecting mechanismcomprises a pair of laterally opposed cam surfaces which contact andmove along the longitudinally outwardly projecting jaw members; and themovement of the rod relative to the cylinder causes the cam surfaces tomove along the jaw members and deflect the jaw members laterally towardand away from one another.
 5. Apparatus as defined in claim 4, wherein:the gripping and cutting assembly further comprises a blade supportbracket which is connected to the cylinder; the jaw members have rearends which are connected together at rear web portion of the blademechanism, the web portion connected to the blade support bracket tomaintain the jaw members in a stationary axial position relative to thecylinder; and the rod is connected to the deflecting mechanism to movethe cam surfaces longitudinally along the longitudinally outwardlyprojecting jaw members.
 6. Apparatus as defined in claim 3, wherein: thegripping and cutting subassembly includes a conduction tube within whichto receive the severed leader portion; the rod includes a hollowinterior passageway extending longitudinally through the rod; and theconduction tube aligns with the interior passageway of the rod. 7.Apparatus as defined in claim 6, wherein: the piston includes a centralhole formed longitudinally through the piston; and the interiorpassageway of the rod and the conduction tube align with the centralhole of the piston.
 8. Apparatus as defined in claim 7, wherein: thecontrol system further comprises a source of low pressure which is lessthan ambient pressure at the interconnector; the tool further comprisesa low pressure chamber into which the low pressure from the low pressuresource is applied, the low pressure chamber connected in communicationwith the central hole of the piston, the interior passageway of the rodand the conduction tube to conduct the low pressure through the centralhole of the piston, through the interior passageway of the rod andthrough the conduction tube; the tool further comprises a collection cuppositioned within the low pressure chamber in which to collect eachsevered leader portion; and the severed leader portion is transportedthrough the conduction tube, the interior passageway of the rod, thecentral hole formed in the piston and into the collection cup by the lowpressure from the low pressure source.
 9. Apparatus as defined in claim8, wherein: the collection cup is selectively removable from the pulland cut tool to empty a plurality of severed leader portions collectedin the collection cup.
 10. Apparatus as defined in claim 2, wherein: thecontrol system further comprises a source of pull fluid pressure and asource of return fluid pressure; the second actuator imparts movement inresponse to an application of fluid pressure to the second actuator; thecontrol system selectively conducts the pull fluid pressure to thesecond actuator to move the blades longitudinally away from the outerone of the printed circuit boards to pull the interconnector thepredetermined distance which positions the connection portion in thefinal position contacting the vias; and the control system selectivelyconducts the return fluid pressure to the second actuator to move theblades longitudinally toward the outer one of the printed circuit boardsto return the blades to the predetermined location where the leaderportion is severed from the connection portion.
 11. Apparatus as definedin claim 10, wherein: the second actuator comprises a cylinder, a pistonmovable within the cylinder, and a rod connected to the piston andextending from the cylinder to impart the movement from the secondactuator; the application of the pull and return fluid pressures causethe piston of the second actuator to move within the cylinder of thesecond actuator and the rod of the second actuator to move with respectto the cylinder of the second actuator; and the movement of the rod ofthe second actuator relative to the cylinder of the second actuator inresponse to the pull and return fluid pressures moves the blades to pullthe leader portion the predetermined distance and to return the bladesto the predetermined location, respectively.
 12. Apparatus as defined inclaim 11, wherein: the pull and cut tool is of a size to be held andmanipulated by hand when assembling the interconnector into theplurality of aligned vias in the corresponding plurality of stackedprinted circuit boards; and the pull and cut tool further comprises aguide member connected to the housing and extending therefrom forcontacting the outer one of the printed circuit boards to establish apredetermined distance between the blades and the outer one of theprinted circuit boards by which to establish the predetermined distancewhich the leader portion is pulled and the predetermined location atwhich the leader portion is severed from the connection portion. 13.Apparatus as defined in claim 11, wherein: the longitudinal movementsubassembly further includes a device connected at a selected positionto the rod of the second actuator to establish the predetermineddistance which the leader portion is pulled.
 14. Apparatus as defined inclaim 10, wherein: the control system comprises a source of open fluidpressure; and the control system selectively conducts the open fluidpressure to the first actuator to move the blades laterally away fromone another to separate the blades laterally from the leader portion.15. A pull and cut tool for assembling a z-axis interconnector into aplurality of aligned vias in a corresponding plurality of stackedprinted circuit boards, the interconnector having a leader portion whichextends through the aligned vias upon beginning to assemble theinterconnector and also having a connection portion which contacts thealigned vias upon completing assembly of the interconnector, the toolcomprising: a gripping and cutting subassembly comprising a pair ofblades and a first actuator connected to the blades and operative tomove the blades laterally toward and away from one another, the firstactuator selectively moving the blades laterally toward one another asufficient distance to penetrate into opposite sides of the leaderportion and grip the leader portion without severing the leader portion,the first actuator also selectively moving the blades laterally awayfrom one another to separate the blades laterally from the leaderportion and release the grip on the leader portion, the first actuatorfurther selectively moving the blades laterally toward one another topenetrate into the opposite sides of the leader portion sufficiently tosever the leader portion from the connection portion; and a longitudinalmovement subassembly connected to the gripping and cutting assembly andcomprising a second actuator operative to move the blades longitudinallytoward and away from an outer one of the plurality of stacked printedcircuit boards, the second actuator moving the blades longitudinallyaway from the outer one of the printed circuit boards to pull theinterconnector a predetermined distance which positions the connectionportion in contact with the vias, the second actuator further moving theblades longitudinally toward the outer one of the plurality of printedcircuit boards to return the blades to a predetermined location adjacentto the outer one of the printed circuit boards where the leader portionis to be severed from the connection portion.
 16. A hand held and handmanipulated pull and cut tool for assembling a z-axis interconnectorinto a plurality of aligned vias in a corresponding plurality of stackedprinted circuit boards, the interconnector having a leader portion whichextends through the aligned vias when starting to assemble theinterconnector and also having a connection portion which contacts thealigned vias upon finishing the assembly of the interconnector, the toolcomprising a pair of blades which move laterally toward and away fromone another and longitudinally toward and away from an outer one of theplurality of stacked printed circuit boards to execute a sequence inwhich the leader portion is gripped, the leader portion is pulled apredetermined distance to position the connection portion in contactwith the aligned vias, and the leader portion is severed from theconnection portion at a location adjacent to the outer one of theplurality of printed circuit boards.
 17. A method of assembling a z-axisinterconnector into a plurality of aligned vias in a correspondingplurality of stacked printed circuit boards, the z-axis interconnectorhaving a leader portion and a connection portion, the connection portioncontacting the vias upon assembly of the interconnector in the alignedvias, the method comprising: inserting the leader portion of the z-axisinterconnector through the aligned vias to establish a starting positionin which a terminal end of the leader portion extends beyond an outerone of the plurality of printed circuit boards; gripping the terminalend of the leader portion with a pinch and cut device when the z-axisinterconnector is in the starting position; pulling the leader portionto move the connection portion of the z-axis interconnector through theplurality of aligned vias to a final position in which the connectionportion contacts the aligned vias, by moving the pinch and cut deviceaway from the outer one of the printed circuit boards while gripping theterminal end of the leader portion with the pinch and cut device;releasing the grip on the terminal end of the leader portion with thepinch and cut device after the z-axis interconnector is in the finalposition; positioning the pinch and cut device adjacent to the outer oneof the printed circuit boards after the z-axis interconnector has beenpulled into the final position and after the grip on the terminal end ofthe leader portion is released; and thereafter severing the leaderportion from the connector portion at a position adjacent to the outerone of the printed circuit boards by use of the pinch and cut device.18. A method as defined in claim 17, further comprising: using opposingblades of the pinch and cut device to grip the leader portion; andpenetrating the opposing blades partially into the leader portion togrip the leader portion.
 19. A method as defined in claim 17, furthercomprising: using opposing blades of the pinch and cut device to severthe leader portion; and penetrating the opposing blades completelythrough the leader portion to sever the leader portion.
 20. A method asdefined in claim 17, further comprising: using opposing blades of thepinch and cut device to grip and sever the leader portion; penetratingthe opposing blades partially into the leader portion to grip the leaderportion; penetrating the opposing blades completely through the leaderportion to sever the leader portion; separating the opposing bladeslaterally away from the leader portion to release the grip on the leaderportion; and separating the opposing blades laterally from the leaderportion prior to gripping the leader portion and after severing theleader portion.
 21. A method as defined in claim 20, further comprising:moving the pinch and cut device away from the outer one of the printedcircuit boards while gripping the terminal end of the leader portion;and positioning the pinch and cut device adjacent to the outer one ofthe printed circuit boards after the z-axis interconnector has beenpulled into the final position and after releasing the grip on theterminal end of the leader portion.
 22. A method as defined in claim 17,further comprising: transporting the severed leader portion away fromthe connection portion immediately after severing the leader portion.23. A method as defined in claim 22, further comprising: collecting aplurality of severed leader portions in a single location which isseparated from the pinch and cut device, the plurality of the severedleader portions originating from a corresponding plurality of z-axisinterconnectors assembled into the printed circuit boards.
 24. A methodas defined in claim 22, further comprising: creating a pressure along apath in which the severed leader portion is transported to the singlelocation which is less than ambient pressure to transport the severedleader portion away from the connector portion to the collectorlocation.
 25. A method as defined in claim 17, further comprising:positioning the pinch and cut device at a predetermined location fromthe outer one of the printed circuit boards prior to pulling the leaderportion.
 26. A method of assembling a z-axis interconnector having aleader portion and a connection portion into a plurality of aligned viasin a corresponding plurality of stacked printed circuit boards with theconnection portion contacting the aligned vias when the interconnectoris assembled into in a final position, comprising: gripping and pullingthe leader portion to move the interconnector into the final positionwith the connection portion contacting the aligned vias; severing theleader portion from the connection portion after the interconnector ismoved into the final position; and accomplishing the gripping, pullingand severing with one pinch and cut device.
 27. A method as defined inclaim 26, further comprising: transporting the severed leader portionaway from the connection portion immediately after severing the leaderportion.
 28. A method as defined in claim 27, further comprising:collecting a plurality of severed leader portions in a single locationwhich is separated from the pinch and cut device, the plurality of thesevered leader portions originating from a corresponding plurality ofz-axis interconnectors assembled into the printed circuit boards.
 29. Amethod as defined in claim 26, further comprising: inserting at least apart of the leader portion into a conduction tube in conjunction withpositioning the pinch and cut device adjacent to the outer one of theprinted circuit boards after the z-axis interconnector has been pulledinto the final position; and transporting the severed leader portionthrough the conduction tube after severing the leader portion from theconnection portion.